Abstract: Monte Carlo method uses statistical sampling theory approximation for solving engineering problems．There are the conflicting issues of model accuracy and time complexity,so experimental model of the Monte-Carlo method was established to estimate pi and theoretically analyze the model accuracy and time complexity．This paper put forward the idea of two improvement program based on the experimental model,and through shift and pretreatment, converted the Tarsus division to reduce the computational complexity of multiplication Mason algorithm to improve efficiency．The simulation results show that in the case of maintaining the same accuracy,the improved experimental model and algorithms can significantly reduce the simulation time,improve the simulation speed,and thus possess a certain value in engineering.

Key words: Monte Carlo-method (MC),Mason rotation algorithm,Algorithm complexity