Gas turbine is very sensitive to the quality of intake air,and low quality of intake air may not only lead to unnormal operating conditions,but also cause irreversible damage. Therefore the development of high-efficiency filter for gas turbine becomes an important task. In order to study the separation performance of an axial cyclone separator under different working conditions,by using numerical simulation method,a multitubular axial cyclone separator is studied. The influence on separation efficiency of different inlet angles and different pressures of dust collecting tube inlet is analyzed,and physical principle of particle’s moving in the separator is explored. Research results show that an appropriate inlet angle can improve separation efficiency of small diameter particles,but it also can depress separation efficiency of larger diameter particles; reducing pressure of inlet of dust collecting tube can improve separation efficiency of small diameter particles,but it has little effect on larger diameter particles. Computing results can provide theoretical reference for design and application of axial cyclone separator in engineering.