Abstract: The rotating-stream plate (RSP) was first developed in 1970 to eliminate the entrained liquid droplet for a turbulent bed contactor in laboratory, and extended to use successfully as trays of plate column. In 1974, it was tested for absorption in industry. Because of its remarkable performances including high load, low pressure drop, high flexibility and long operating period, the range of its application has been rapidly enlarged. It has played an important role in industry such as heat and mass transfer operation, entrainment elimination and dust removal. The method of cooling hot saturated air by cold water, which is convenient, speedy and quite accurate, is used to measure the tray efficiency based on gas phase. A 300mm diameter perspex column fitted with three test trays spaced 300 mm apart was used. Above the test section, an entrainment eliminator of the RSP type was located. The liquid load U varied from 7.17 to 135m3/m2h (corresponding to liquid flow rate L from 0.5 to 9.4m3/h). The superficial gas load factor F, varied from 0.56 to 4.51 kg0.5/m0.5s(correspond-ing to superficial gas velocities of 0.52 to 4.21m/s). Five different RSTs and two sieve trays were investigated. The effects of gas load, liquid load, structure of the downcomers and elevation angle on the tray efficiency were systematically studied and the experimental data in the jet region were correlated. The normal operatingrange and the performance of the RST were compared with those of the sievetrays and the industrial test in Sichuan Chemical Plant were briefly summarized.