The present invention discloses a method for ensuring wireless data transmission by using fountain code-based symmetrical encryption. The method comprises the following steps that: 1) K encrypted source data packets are obtained; 2) fountain code encoding packets are obtained, the serial numbers and encoding information of the fountain code encoding packets are interposed into the headers of the fountain code encoding packets; 3) when a legitimate receiving end successfully completes fountain code decoding according to the received fountain code encoding packets, and restores the encrypted source data packets, the legitimate receiving end constructs a serial number set V according to the serial numbers of all the currently-received fountain code encoding packets; 4) a legitimate transmitting end performs XOR encryption on a random bit sequence k by using fountain code encoding packet data corresponding to all serial numbers in the serial number set V so as to obtain an encrypted random bit sequence k'; and 5) the legitimate receiving end decrypts the encrypted random bit sequence k' to obtain the random bit sequence k, and then decrypts the encrypted source data packets according to the random bit sequence k to obtain original data streams. With the method adopted, the security of wireless data transmission can be effectively improved, and the feedback load of the legitimate receiving end can be decreased.