a data file decryption method , a decryption device and a data broadcasting system are disclosed , which are applied to a data broadcasting service . among them , the data file decryption method includes the steps of : receiving the file delivery information which includes a data file identification and a key file identification corresponding to the data file ; receiving the corresponding data file and key file according to the data file identification and the key file identification ; and decrypting the data file according to the key file . according to the data file decryption method , decryption device and the data broadcasting system of the present invention , by setting the data file identification and the corresponding key file identification in the file delivery information and receiving the corresponding file according to the data file identification and the key file identification , the resource dissipation due to a large quantity of useless information received at a terminal is avoided , and the file to be received can be quickly located by the terminal , so that the time delay due to the decryption of a data file is avoided , and the service experience for users is improved .