During the handover process of high-speed trains, due to the influence of path loss and terrain, the Reference Signal Receiving Power (RSRP) fluctuates up and down, and the handover decision method based on the traditional A3 event will cause ping-pong. The occurrence of handover and the drop in handover success rate. To solve this problem, a handover algorithm based on an improved gray-Markov model is proposed. The received power of the reference signal is processed and predicted by an improved grey-markov model, and the handover process is executed by using the processing result as the handover decision based on the preloading method. The simulation results show that by using the improved handover algorithm, the fluctuation of RSRP values received by the train can be significantly improved, the ping-pong handover probability is lower, and the handover success rate can be effectively improved.