The invention relates to a real-time repetition removal and transmission method for data in a 
network file system, and belongs to the technical field of 
computer data storage. The method comprises the following steps of: setting a file 
metadata table, a data block index table and a file composition table in a 
client and a 
server respectively, and setting a to-be-transmitted 
message queue for storing data and updating message in the 
client; receiving and responding an operating command initiated to the 
network file system by a 
client application program through a 
file system drive by the client, wherein the operating command comprises the operation of creating a new file, writing data into an existing file, reading the data from the existing file and deleting the existing file; and settinga 
network service interface for uploading and downloading data block contents and receiving and answering client message in the 
server. The method can delete the repeated data so as to save the storage space, avoid transmitting the existing data of the opposite side between the client and the 
server and reduce the overhead of network bandwidth; meanwhile, the method supports a file blocking method of 
fixed length and unfixed length so as to improve the 
utilization rate of the storage space.