The tearing performance of polyvinyl chloride(PVC) coated polyester fiber membrane commonly used in membrane structure was experimentally studied in detail. Uniaxial tearing tests including single tongue, double tongue and trapezoid shaped methods were carried out and the failure mechanism and main characteristics of them were analyzed. It is found that trapezoid tearing test is relatively simple and much closer to the plane loading condition of tearing of membrane in practical structure, its test result is relatively stable, so that it is worthy recommending tearing test method. The experimental results are compared and the applicability of the three methods is examined. The biaxial central tearing method was used to test the type I slit prefabricated in the center of the cruciform specimen. The initial slit length is 40mm and at an angle of 0°, 45° and 90° to the warp direction. The crack propagation process under 1∶1 orthogonal biaxial loading was observed and the strain field distribution on membrane surface was measured by non contact method, resulting in a conclusion that the tear strength and crack propagation mode are affected significantly by the slit angle and the maximum strain during the process always appears in the del zone of the crack tip.