Nowadays, two or even more cyclone separator series are employed to work together when a single cyclone separator can not meet the corresponding requirements of separation performance and pressure drop.However, little research dedicating to it has been reported in the past.In order to evaluate the influence of different materials and pressure drop distribution between two-stage separators, the single-stage and overall collection efficiencies with Gray shale and FCC catalyst are investigated under ambient temperature and atmospheric pressure conditions.In addition, the effects of gas inlet velocity on separation efficiency and pressure distribution of two-stage cyclone, as well as the optimal pressure drop distribution matching relation between two separators are experimentally studied.The experimental results show that: i) the separation efficiency of a single stage and overall collection efficiencies increased with the increasing inlet velocities and pressure drop ratio when the FCC catalyst was used.ii) the first-stage efficiencies and overall collection efficiencies of the Gray shale decrease linearly as inlet velocities increased from 15m/s-21m/s, while the second-stage efficiency changes nonlinearly with the increasing inlet velocities.The overall collection efficiencies reach a peak when the inlet velocity is 15m/s; and iii) when the total pressure drop of the two-stage cyclone is a constant,.the overall separation efficiency is higher when P1