do i need to declare alcohol under 12%

There is no need to declare for alcohol < 12%

See below link:
http://english.customs.gov.cn/publish/portal191/tab47816/info391217.htm


1,500ml or above of alcoholic drinks (containing 12% or above alcoholic content); 400 sticks or above of cigarettes; 100 sticks or above of cigars; 500g or above of tobacco.