A peridynamic model for envelope material was established based on peridynamic theory. First, the basic theory of peridynamic and the major property of envelope material were illustrated. The material was scattered into particles, and based on a classic peridynamic model of composites, the components of constitutive force and strain energy density of each particle were analyzed under a unique condition of intertexture. The constitutive function and peridynamic parameter were divaricated thus completed the model. Emulation of mechanical property was conducted using dynamic relaxation method. The results show a correspondent stress state under tension with an alternative numerical result. The tensile modulus and the load-strain curve are in accordance with the lab results.