Which attractions in China is more beautiful to visit in December?

Generally speaking, the most attractive sightseeing in China in Dec. is snow-covered landscape.
So you can go to Harbin. The ice and snow are Harbin's greatest attraction.
There are multicolored ice lanterns, vivid ice and snow carvings and exciting ice sports. You can fully enjoy yourselves. Besides, Xuxiang is also highly recommended.

Thank you Judy for your reply. I planned to follow package tour to huangshan in December. Any advice?

First of all, I would tell you that West Sea Canyon and Tiandu Peak would close in Dec. To join a tour to visit the mountain, you can try to consult Travel China Guide. They arrange many tours with superb service. Here is the contact for your convenience:
traveltravelchinaguide.com