A method and device for identifying junk picture files, which are used for a server side to identify junk picture files in cached network data. The method comprises: obtaining a directory to be detected; determining whether the number of files in the directory is greater than or equal to a first preset value; if so, determining whether file names of the files in the directory contain keywords which represent the cached network data; if the keywords are contained, determining that the files in the directory are the cached network data, and then, determining whether keywords which represent useless picture files exist in the cached network data, so as to find out whether junk picture files exist; if the junk picture files exist, identifying the found picture files as cached junk picture files; and recording a directory path where the cached junk picture files are located. By means of the above solution, the cached network junk picture files can be accurately identified.