Thanks everyone.The problem was solved on my computer.(The customer's DB has resored by backup)

I executed :

sp_Msforeachtable @command1="print '?' dbcc dbreindex('?')"

reindex all the user table,then run the check again no error...

First thanks for you.I execute the follow script :

sp_configure 'show advanced options',1

go

sp_configure 'allow update', 1

then I restart the SQL Server service

then I execute:

truncate table sysindexes

the reply is:

could not allow truncate...