optimization of the pulsejet mainly depends on expensive and difficult experiment measurement. With the development of computer technology and Computational Fluid Dynamics (CFD) [5-7], numerical simulation is utilized to recognize complicated two-phase reaction turbulent flow process and to direct pulsejet’s optimum design [8], which can reduce the cost and the cycle of experiment research. Estimation model [9] has been established and been used to predict performance of valveless pulsejet, which is based on thermodynamic and acoustic theory and lacks of the information of the threedimension turbulent reaction flow field and the consideration of influence factors in pulsejet. Furthermore, CFD can be used to observe combustor’s detailed internal parameters, which is very hard or extremely expensive if just gained by experiment study and able to provide excellent help in aero engine optimization. In this paper, an investigation is conducted in order to understand how china-type pulsejet performance depends on the length of tail and the combustor, by utilizing numerical simulation of multi-cycle working process in such pulsejets. So, computer simulations are performed to study multi-cycle working process in china-type valveless pulsejet and to predict the performance of researched objects by using of general CFD package (CFX TM 11.0).