The invention discloses a method for realizing a recording function by train control vehicle-mounted equipment. The method is characterized in that the data recording function of the train control vehicle-mounted equipment is realized by an isolation recorder; the isolation recorder communicates with a vehicle-mounted train control system through a communication board; the train control vehicle-mounted equipment and the isolation recorder are two completely independent systems, and the train control vehicle-mounted equipment system and the isolation recorder communicate through an isolation interface of the communication board to realize data transmission; the isolation recorder independently supplies power, a communication interface of the communication board and the isolation recorder isan isolation interface, and the communication board sends key information in the working process of all the train control vehicle-mounted equipment to the isolation recorder in a one-way mode throughthe isolation interface; and the isolation recorder only records the key information sent by the train control vehicle-mounted equipment, and the isolation recorder does not send any information to the outside so as to avoid influencing the train control vehicle-mounted equipment work after the isolation recorder breaks down. The method for realizing the recording function by the train control vehicle-mounted equipment has the technical advantages that the isolation and the independence of the recording function and the safety function are realized, and the influence of the recording functionon the safety function and the hidden danger brought by the recording function are reduced.