A series of tests were carried out to study the mechanical properties of PTFE membrane material. The tensile failure mechanisms of PTFE membrane material were discussed, and the resistance uncertainty of PTFE membrane material was analyzed. The effects of cyclic tensile, temperature, damage, welding connection, artificial accelerated aging on the material tensile properties were studied. Results show that the strain at break in warp is less than that in weft and the tensile strength in warp is slightly higher than the tensile strength in weft. With temperature increasing, the tensile strength of membrane material decreases. The tensile strength of seams of welding membrane material can achieve 90% of that of base material. There is significant reduction of tensile strength, of which the degree is related to the sample position and folding times. When the stress amplitude of cyclic tensile tests is higher, the tensile curves of PTFE membrane material after cyclic tensile tend to be linear. The accelerated aging can lead to the decreasing to PTFE membrane material tensile strength, of which the degree is not obvious.