Hi, DP members, I have mede a 301 redirect from feir.com.cn and oaso.cn to my new site http://if20.net. The first site feir.com.cn is PR4 but I dont want to use it anymore. I dont know whether it would help my if20.net to get PR rank?
Yes, that's the purpose of a 301 redirect, to transfer pagerank accordingly. Essentially it's just telling search engines "HEY! WE MOVED! I'M OVER HERE NOW!"
It should redirect all of it and by the next time you mean after the next PR update, then yes, the next time.