Series tests were carried out for the new airship envelope fabric Uretek3216L. First, uni-axial cyclic tests were conducted. And then, on the basis of the multi-function bi-axial tension tester developed in SSRC, bi-axial tension tests with five stress ratios were carried out with particular test protocol. Detailed experiment results and elastic modulus and Poisson's ratio were obtained. The stress-strain relationship and elastic modulus of the membrane material under uni-axial tests and bi-axial tests were obtained at different cycle numbers. Moreover, the relation formula between coupled elastic modulus and stress ratios was proposed and bi-axial stress-strain surfaces were presented. The results have shown that, for the uni-axial cyclic tests, from the 1st to the 15th, the elastic moduli increase by 20.7% in warp and 39.1% in weft of the initial elastic modulus respectively; and the 2nd cycle has the biggest increments in both directions, which are about 60% of the total increment in relevant direction. For bi-axial tensile tests, when the stress ratio increases, the warp direction's coupled elastic moduli increase and the weft direction's decrease gradually.