The invention discloses a polytetrafluoroethylene electro-catalysis porous membrane and a preparing method thereof. The membrane is composed of a basement membrane and a conducting layer loaded on the surface of the basement membrane, or an electro-catalysis layer is loaded on the surface of the conducting layer. The basement membrane is a polytetrafluoroethylene formed by two-way stretching, and the conducting layer is made of multiwalled carbon nanotubes or a mixture of the multiwalled carbon nanotubes and graphene. The preparing method includes the steps that conducting layer substances are evenly dispersed in solvent to obtain dispersion liquid A; ethyl alcohol is used for conducting pretreatment on the basement membrane; the basement membrane is fixed into a sand core filtering device, and the conducting substances in the dispersion liquid A are deposited on the surface of the membrane and dried to obtain a polytetrafluoroethylene electro-catalysis membrane; before drying, dispersion liquid of electro-catalysis substances is deposited on the surface of the conducting layer with the sand core filtering device and dried to obtain the polytetrafluoroethylene electro-catalysis porous membrane. Compared with a membrane using a carbon membrane as a basement membrane, the polytetrafluoroethylene electro-catalysis porous membrane is good in flexibility and low in cost; the preparing method is simple and easy to operate.