A method and a system for previewing file information are disclosed. The method includes: storing file information of files in a file system to a predetermined cache with a uniform file format, and establishing a file information identification number list including a unique identification number for each of the information in the cache; reading the file information identifying number list from the cache, and querying whether a file information identifying number of a file to be previewed exists in the file information identifying number list; and directly reading file information of the file to be previewed from the cache via the uniform file format if the file information identification number of the file to be previewed exists in the file information identifying number list. The present disclosure can avoid complicated decoding processes and implement a rapid preview of the file information.