有好心人士教我的，主要是加上
AuthzSVNAccessFile D:\svn\svn_access_file
例如:
DAV svn
SVNParentPath d:/svn/
AuthType Basic
AuthName "Subversion repository"
AuthUserFile D:\svn\svn-auth-file
AuthzSVNAccessFile D:\svn\svn_access_file
Require valid-user
而 svn_access_file 的樣子如下
[groups]
cf_hw = ct_lin, jimmy, square
lba_hw = ct_lin, vicent, yungwei
ecc_hw = ct_lin, Gary
[repository:/]
@cf_hw = rw
[LBA:/]
@lba_hw = rw