A combined type gas-liquid-solid three phase separation method integrates the main structures of a convergent-divergent type, a centrifugal type, a deflector type and a screen type mist eliminators. A spiral guide plate is arranged at the outer end of a guide cylinder based on a convergent-divergent type. A spiral guide cover is arranged in an annular clearance consisting of two conic casings. A gas phase containing liquid-solid particles speeds up in the annular clearance and meanwhile makes whirling motion. The separation efficiency is improved. The gas phase converged, diverged and whirled is deflected, enters the next whirling channel and is subsequently deflected again. Finally, the gas phase is continuously separated by a screen type mist eliminator. Liquid-solid entrainments in the gas phase are reclaimed by the combined type gas-liquid-solid three phase separation device, and return to the liquifying layer of a reactor. The separation efficiency of the device designed with the method can reach more than 99%. The device can meet the requirements of the existing slurry bed reactors for continuous operation for more than 180 days. The method can even meet the requirements for efficiently recovering entrainments in other reaction processes.