Abstract: A new type of tray called Type-95 tray with a bigger effective mass transfer area and higher tray efficiency is developed and tested, whose downcomer structure is specially designed with a new concept. The fluid dynamics characteristics of the tray, i.e., pressure drop, weeping, liquid height in the downcomer and flow pattern on the tray, are determined on a test rig with a diameter of 1000 mm by air-water system at atmospheric pressure. The experimental results are compared with those of the traditional sieve tray. It indicates that the Type-95 tray has the advantage of lower pressure drop and bigger flux. The related mathematical equations for designing Type-95 tray are derived from the experimental data, which can be basically applied to the design of an industrial tray within allowable engineering deviation. In addition, the eddy and backmixing of liquid on the tray can be eliminated effectively by installing appropriate deflectors. As a result, the liquid flow pattern on the tray is almost changed into plug flow, which might cause an increase of mass transfer efficiency of the tray.