Help me!!! About Locale Settings in Gentoo Linux

I reinstalled my gentoo linux system on my pc today,and finally everything went well except for one thing:The locale settings.
-- I already done "eselect locale set" to zh_CN.utf8,and then my "locale" output seems to be correct,and the /etc/env.d/02locale file is correctly set as well.But when I reboot again,all of my locale settings changed from "zh_CN.utf8" to "POSIX",which ended up the whole system is in English.How can I resolve this issue guys?Thanks.