The invention discloses a file transmission system for an electric power system. The file transmission system comprises a mobile terminal used for acquiring a first data file including accident field information, an encryption U disk stored with an encryption file, a mobile terminal female seat used for fixing the mobile terminal, a storage server used for receiving the encrypted first data file sent by the mobile terminal female seat through the Internet, and a decryption server provided with a decryption chip, wherein the mobile terminal female seat is provided with a USB female port, after the encryption U disk is connected with the mobile terminal female seat, if a correct cipher for access to the encryption U disk is received, the first data file is encrypted on the basis of the encryption file, and the decryption server is used for decrypting the encrypted first data file through the decryption chip and sending the first data file after decryption to terminal equipment initiating a decryption request. The file transmission system solves a technical problem of relatively low safety existing in an electric power system employing a mobile terminal to transmit audio video files in the prior art.