Abstract: Short fiber reinforced ethylene propylene diene monomer(EPDM) film material is a new type of thermal insulation and structural materials, which is applied in the cladding of solid rocket motor with low density, ablative resistance and good mechanical properties. In order to establish a general criterion for rate dependent anisotropy in quasi-static conditions, rate dependent function and rate intensity factor methods were introduced to extend Tsai-Hill strength criterion, which was used to predict the tensile strength in different off-axis directions. Studies show that axial strength and shear strength increase with the strain rate. Compared with rate intensity factor method, Tsai-Hill strength criterion based on rate dependent function method has higher prediction accuracy. Meanwhile, the prediction error of rate intensity factor method has strong relations with selection of reference rate and function expression of rate intensity factor.