best tranportation/route from Yading(亚丁) to Téngchōng(腾冲)

I've never been to Yading before, though I have been to Tengchong. Looking on the map, I think your plan is the best one! I'm not sure what buses out of Shangri-la are like. There are probably more frequent ones to Lijiang than Dali/Xiaguan, so you might even need to change buses in Lijiang. I traveled once from Dali to Tengchong; I don't think there was a direct bus. I think we had to change in Baoshan. But I can't remember for certain.

The alternative would be to head from Yading to the main rail line, catch a Kunming-bound train as far as a transport stop called Guangtong, and then continue on buses from there.

I don't know which way around is likely to be faster, but my best guess is the first. Your 20 hours sounds optimistic.

Your routing should be Yading - Xiangcheng - Zhongdian - (Lijiang) - Dali - Baoshan - Tengchong. Many things to see on this route: very foolish to rush right through. Tengchong is interesting enough, but not extraordinarily so. Certainly not extraordinary if you've ever been to Yellowstone.

Fastest way,I suggest you take the plane.
In the morning,from yading airport fly to chengdu,afternoon from chengdu fly to tengchong airport.
if you from yading to Shangrila, need 7 hours.....

There is a bus from Daocheng town to Shangri-la that leaves early in the morning. From Shangri-la you can take a bus to Dali. Depending on what time the bus from Daocheng town reaches Shangri-la, you can choose to take a night sleeper bus to Dali. Finally you can take the bus from Dali to Tengchong.

20 hours is wildly optimistic. Using public transport and being subject to the realities of bus scheduling, I suspect if you leave Yading the morning of Day 1, you might get to Tengchong by the afternoon of Day 3. Lots of good stuff to see on the way but that requires more time. Shame if you have to rush through it.

There is a bus from Daocheng town to Shangri-la that leaves early in the morning. From Shangri-la you can take a bus to Dali. Depending on what time the bus from Daocheng town reaches Shangri-la, you can choose to take a night sleeper bus to Dali. Finally you can take the bus from Dali to Tengchong.

great :)
is what i tought ...thanks for your answer :)

Your routing should be Yading - Xiangcheng - Zhongdian - (Lijiang) - Dali - Baoshan - Tengchong. Many things to see on this route: very foolish to rush right through. Tengchong is interesting enough, but not extraordinarily so. Certainly not extraordinary if you've ever been to Yellowstone.

i'm already been in Shangrila(Zhongdian), Dali and Lijiang (in Lijiang twice)...
which other places to see on this route ?

In that case, take the Zhongdian-Jianchuan bus (this goes through Qiaotou), takes about 4 hours in daytime. Switch to minibus to Shaxi (another 45 minutes) and spend at least a couple of days/one night in that village. Then depending on time, you can get from Shaxi to Jianchuan (minibus) to Dali (frequent public buses) in under 4 hours. Then Dali to Tengchong bus. The slower but more interesting way would be to bus from Jianchuan west to Lanping then Nuodeng salt village (near Yunlong), stay there. Then south to Baoshan, where you can express bus it pretty quick to Tengchong. Looks like Jianchuan-Yunlong bus leaves early in the morning (07:00) takes 6 hours. Yunlong-Baoshan also a couple of buses leaving first part of morning, takes 3-4 hours. I've always wanted to do this "back door route" that few foreigners ever seem to get to, but haven't made it happen yet.

In that case, take the Zhongdian-Jianchuan bus (this goes through Qiaotou), takes about 4 hours in daytime. Switch to minibus to Shaxi (another 45 minutes) and spend at least a couple of days/one night in that village. Then depending on time, you can get from Shaxi to Jianchuan (minibus) to Dali (frequent public buses) in under 4 hours. Then Dali to Tengchong bus.

so it would be:
-bus from Yading to Daocheng (around 2 hours)
-bus from Daocheng to Shangri-La(Zhongdian) (around 8 hours)
-bus from Shangri-La(Zhongdian) to Jianchuan (around 4 hours)
-minibus from Jianchuan to Shaxi(45 minutes) [couple of days in Shaxi village]
-then again Shaxi to Jianchuan and then bus from Jianchuan to Dali (around 2 hours)
-then Dali to Tenchong (4 hours and 30 minutes)

So it's around 24 hours from Yading to Shaxi village and around 8 hours (including waiting time) from Shaxi to Tengchong.
this one:
https://tinyurl.com/y8zfc5s9

The slower but more interesting way would be to bus from Jianchuan west to Lanping then Nuodeng salt village (near Yunlong), stay there. Then south to Baoshan, where you can express bus it pretty quick to Tengchong. Looks like Jianchuan-Yunlong bus leaves early in the morning (07:00) takes 6 hours. Yunlong-Baoshan also a couple of buses leaving first part of morning, takes 3-4 hours.

-bus from Yading to Daocheng (around 2 hours)
-bus from Daocheng to Shangri-La(Zhongdian) (around 8 hours)
-bus from Shangri-La(Zhongdian) to Jianchuan (around 4 hours)
-bus from Jianchuan to Lanping (around 3 hours)
-bus from Lanping to Yunlong (around 2 hours)[stay in the near Nuodeng salt village ]
-bus from Yunlong to Baoshan(around 3 hours)
-bus from Baoshan to Tengchong (2 hours)

Lanping then Nuodeng salt village (near Yunlong), stay there

there is a bus from Lanping to Nuodeng(near Yunlong) ?
or from Nuodeng(Yunlong) have to go back to Jianchuan?

I've always wanted to do this "back door route" that few foreigners ever seem to get to, but haven't made it happen yet.

yeah it's fascinating :) thinking about it.