【Purposes】The research on advanced stratospheric airships in China is mainly at the
conceptual design stage， lacking specific mechanical performance evaluation to promote their development.【Methods】On the basis of the uniaxial cyclic tensile test of airship membrane material， the mechanical performance of the semi-rigid stratospheric airship （L=120 m） with carbon fiber skeletons and inflatable rings was analyzed. The influence of carbon fiber skeletons and inflatable rings， number of inflatable rings， internal pressure of the inflatable rings， and internal pressure of envelope on mechanical performance of the envelope was investigated， and the evaluation index of inflatable ring parameters was proposed. 【Findings】The research results indicate that compared with the traditional no-rigid airship without skeletons，the airship designed in this paper is significantly reduced in the maximum deformation of envelope， and is more uniform in the stress distribution of envelope. As the number of inflatable rings increases， the maximum deformation and maximum stress of envelope decrease， and the stress distribution of envelope is more uniform. The optimal recommended number of inflatable rings is 6. With the increase of the internal pressure of the inflatable rings，the maximum deformation of envelope decreases， and the maximum stress shows a trend that stabilizes first and then increases. The optimal recommended value of the internal pressure of the inflatable rings is about 200 kPa. As the internal pressure of the envelope increases， the contribution rate of internal skeletons to the improvement of mechanical properties decreases.