The utility model relates to an evaluating device for a movable pervaporation membrane, which is applied to the performance evaluation of the pervaporation membrane. The evaluating device for a movable pervaporation membrane is characterized in that a lower-layer spacer plate of a framework is fixedly provided with a raw material tank, a vacuum pump and a raw material tank thermostatic water bath; the raw material tank is in jacket type; the upper part of the right side of an upper-layer spacer plate is fixedly provided with an electric control cabinet panel, on which a temperature display meter, a pressure display meter, a pressure setting meter, a power supply control switch and a status display lamp are fixed; the lower part of the right side of the upper-layer spacer plate is fixedly provided with a valve panel, on which a manual gate is arranged; the left side of the upper-layer spacer plate of the framework is fixedly provided with a feeding pump, a membrane evaluating pool, an evaluating pool thermostatic water bath and two cold traps; and the membrane evaluating pool is arranged on the upper-layer spacer plate of the framework, and the two cold traps are fixed behind the evaluating thermostatic water bath. The evaluating device for a movable pervaporation membrane has the advantage of stably moving on a flat ground freely; and the device can run either in a laboratory or on an industrial spot.