The invention relates to a file transmitting method and system, sending end equipment and receiving end equipment, and the method comprises the steps: carrying out the random arrangement of all encryption sub-files corresponding to a to-be-transmitted target file, wherein the sequence of all encryption sub-files can be disturbed so as to improve the difficulty for an illegal person to decrypt an original file, and improve the transmission safety of file information; furthermore, the encrypted file and the information table thereof are respectively transmitted according to different lines, wherein even if an illegal person monitors the transmission line of the encrypted file, the information table cannot be obtained from the line at the same time; therefore, on the one hand, the illegal person cannot recover the original logic sequence of each encrypted sub-file according to the segment serial number and the arrangement sequence in the information table; on the other hand, the illegal person cannot obtain the encryption key and cannot crack the decryption key according to the encryption key, that is, the illegal person cannot decrypt each encrypted sub-file, so that the difficulty is provided for the illegal person to obtain the target file, and the information security of the transmitted target file is improved.