Is it possible to sleep overnight at kunming airport?

Yes, you can stay and take some rest in the public area. Or you can find a hotel nearby the airport.

Thanks, I was actually there last night and there are quite a few people scouting the area to see if travlers need hotel. I gave in to one since I thought the airport was closing and reopening at 5am. They took me to some beaten down hostel like place where all the rooms shared a bathroom for 170rmb. Now that I think back, It was quite a risky thing I did considering I did not know where they were taking me, my mandarin was horrible and I had a hard time communicating and understanding them.