backup log 数据库名 with no_log
dbcc shrinkdatabase('数据库名')

------解决方案--------------------
备份日志后清除日志或压缩日志.

清除日志：

  
DECLARE @LogicalFileName sysname,
       @MaxMinutes INT,
       @NewSize INT
USE     szwzcheck             -- 要操作的数据库名
SELECT  @LogicalFileName = 'szwzcheck_Log',  -- 日志文件名
@MaxMinutes = 10,               -- Limit on time allowed to wrap log.
       @NewSize = 20                  -- 你想设定的日志文件的大小(M)
-- Setup / initialize
DECLARE @OriginalSize int
SELECT @OriginalSize = size  
 FROM sysfiles
 WHERE name = @LogicalFileName
SELECT 'Original Size of ' + db_name() + ' LOG is ' +  
       CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +  
       CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
 FROM sysfiles
 WHERE name = @LogicalFileName
CREATE TABLE DummyTrans
 (DummyColumn char (8000) not null)
DECLARE @Counter   INT,
       @StartTime DATETIME,
       @TruncLog  VARCHAR(255)
SELECT  @StartTime = GETDATE(),
       @TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
DBCC SHRINKFILE (@LogicalFileName, @NewSize)
EXEC (@TruncLog)
-- Wrap the log if necessary.
WHILE     @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time  
     AND @OriginalSize = (SELECT size FROM sysfiles WHERE name =  
@LogicalFileName) 
     AND (@OriginalSize * 8 /1024) > @NewSize 
 BEGIN -- Outer loop.
   SELECT @Counter = 0
   WHILE  ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
     BEGIN -- update
       INSERT DummyTrans VALUES ('Fill Log') 
       DELETE DummyTrans
       SELECT @Counter = @Counter + 1
     END  
   EXEC (@TruncLog) 
 END  
SELECT 'Final Size of ' + db_name() + ' LOG is ' +
       CONVERT(VARCHAR(30),size) + ' 8K pages or ' +  
       CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
 FROM sysfiles  
 WHERE name = @LogicalFileName
DROP TABLE DummyTrans
SET NOCOUNT OFF
  
把szwzcheck换成你数据库的名字即可，在查询分析器里面运行。  
有全角的空格(为了显示好看),你自己把他换一下.  


收缩日志：

企业管理器--所有任务--收缩数据库--文件--选日志文件收缩




------解决方案--------------------
SQL code


--收缩日志代码，hh为数据库名称

dump tran hh with no_log
backup log hh with no_log
dbcc shrinkdatabase(hh)

------解决方案--------------------
如果日志为自动增长时,
检查一下硬盘的空间是否已满..