select cu.flowers,
(select  count(b.userid)+1 us  from  cm_users_tbl b WHERE  CU.uservotes<b.uservotes ) as rank,
cu.UserID,
cu.UserBBName,
cu.UserPhoto,
cu.UserVotes,
gender=case cmi.gender when 1 then '男' else '女' end, 
Convert(varchar(20),datediff(Month,Birthday,getdate())/12) +'岁'+ Convert(varchar(20),datediff(Month,Birthday,getdate())%12) + '个月' as age
from CM_Users_Tbl cu inner join CM_UserInfo_Tbl cmi on cmi.userid=cu.userid
order by cu.UserVotes desc

select cu.flowers,
(select  count(b.userid)+1 us  from  cm_users_tbl b WHERE  CU.uservotes<b.uservotes ) as rank,
cu.UserID,
cu.UserBBName,
cu.UserPhoto,
cu.UserVotes,
cmi.gender 
Birthday
from CM_Users_Tbl cu inner join CM_UserInfo_Tbl cmi on cmi.userid=cu.userid
order by cu.UserVotes desc

建议 在uservotes 和 userid 字段上创建索引。
或者  创建一个包含索引 比如 
create index idx_name on CM_Users_Tbl (uservotes desc,userid desc) 
include (flowers,UserBBName,UserPhoto)

------解决方案--------------------
探讨

(select count(b.userid)+1 us from cm_users_tbl b WHERE CU.uservotes<b.uservotes ) as rank,

这快应该是慢的原因，会做很多全表扫描
你ctrl + L 查看一下执行计划就知道了


------解决方案--------------------
(select count(b.userid)+1 us from cm_users_tbl b WHERE CU.uservotes<b.uservotes ) as rank,
count(b.userid)+1 us 这个中间怎么有个us,啥意思？不懂

------解决方案--------------------
子查询(select count(b.userid)+1 us from cm_users_tbl b WHERE CU.uservotes<b.uservotes ) as rank,
是慢的主要原因

------解决方案--------------------
你这索引假脱机 耗费了45%。
可以试一试 清理缓存，再试一试。

------解决方案--------------------
1. CM_UserInfo_Tbl CM_Users_Tbl 两个表分别有多大数据量？
2.(select  count(b.userid)+1 us  from  cm_users_tbl b WHERE  CU.uservotes<b.uservotes ) as rank
  这个如果只是用来做排序，用row_number() 来实现比较合适

------解决方案--------------------
cu.UserPhoto,
是否图片？

去掉这个字段试下。