I find the reason for this problem.
Because the function scandir() is disable on my hosting.
Edit php.ini
on the line of disable_functions
del, “scandir”
this is snapshot of my ftp,
http://b7x24.com/tm2.jpg
i saw the default theme on beginning.But after I installed a new theme, it just show the Current Theme. no others theme.
Thanks for your reply.
No multi-site
Permissions of themes folder is 777
WP is new install, no any plugins yet.