The invention relates to a fault recording data transmission method based on UDP and belongs to the technical field of substation automatic digital recording. A data buffer area is built at a transmitting end, to-be-transmitted data is divided into isometric data and saved into the buffer area, the transmitting end transmits the data to a receiving end in a UDP manner, the receiving end regularly inquires the received data, and if frame missing or mistaken frames occur, the transmitting end starts a retransmitting mechanism to transmit the loss data packets. During the whole transmission process, the receiving end uses a multithread data processing manner and monitors whether the receiving end buffer area is full or not at the same time to bring convenience to emptying. By the method, packet loss during efficient UDP transmission can be guaranteed, transmission efficiency and stability are increased, and data transmission stability of a fault recorder is increased.