Hi, want to visit jiuzhaigou a week after Chinese new year ( winter period )

What cost do you refer to? Entrance ticket fee or transportation fee? Anyway, the entrance fee is CNY80 per person at that time.

Although it snows then, the road to JZG won't have closure and the buses from Chengdu to the valley would depart as usual. Don't worry! The direct buses can be taken at Xinnanmen Bus Station or Chadianzi Bus Station. They leave in the morning and the bus fare is CNY143-165 per person.