The invention relates to a rotary membrane separation device and an application thereof. The two ends of a hallow shaft are fixed on the bracket; the hollow shaft is sheathed with a revolving drum the two ends of which support on the hollow shaft in a revolving and free manner; the chamber of the revolving drum is communicated with the cavity of the hollow shaft through the communication hole on the hollow shaft; the excircle of the revolving drum is provided with a collecting pipe along the axial direction; a communication opening is arranged at the joint of the collecting pipe and the revolving drum; the chamber of the collecting pipe is communicated with the chamber of the revolving drum through the communication opening; the collecting pipe is provided with a filtering membrane component the two side surfaces of which are stuck with filtering membrane materials; the effluent opening at the bottom part of the filtering membrane component is communicated with the collecting pipe; the filtering membrane component chamber constitutes a channel with the cavity of the hollow shaft via the collecting pipe chamber and the revolving drum chamber; one port of the hollow shaft is connected with a suction pump and the other end is connected with a standby conduit; one end surface of the revolving drum is fixedly provided with a transmission gear which is driven by a motor. The device can conveniently realize the separation of particulate matters, colloid, microorganisms and molecular mixtures in water or other solvent medium.