Aiming at the situation that the parameters of the classical washout algorithm of the motion platform of the aircraft simulator are not selected properly, which causes a large error to the dynamic fidelity and affects the simulation effect, an improved whale optimization algorithm combining simulated annealing and adaptive variation is proposed. Combining with the vestibular system, a human perception simulation model is established, and the dynamic fidelity problem is transformed into the problem of finding the optimal parameters of the filter of the washout algorithm. The test function proves that the improved whale algorithm has better searching effect than traditional whale algorithm, particle swarm optimization algorithm and genetic algorithm. In addition, the simulation experiment also shows that compared with the classical washout algorithm and the traditional whale optimization algorithm, the improved whale optimization algorithm had the fastest convergence speed, the washout time was shortened by 83.3% and 33.4%, respectively, and the motion space was optimized by 45.2% and 26.1%. It is proved that the improved whale algorithm has strong robustness, and the simulation effect of motion washout is obviously improved.