Composite materials for tritium were determined through the technique of trapping the permeating tritium with water. Testing on mechanical properties such as tensile experiment was performed for both Polyvinylidene chloride (PVDC) films and composite materials. Chemical performance was determined by calculating the dissolved rate in the acid and alkali, breaking strength, loss rate and stripping strength loss rate. The results showed that the gas tritium permeability through the composite materials was 3.44×10‒10 m3/(m2∙s), 1/70 relative to the PVC films. The fracture strength of PVDC films was increased by about 20 times, and the warp and weft breaking strength was 721 N. After the immersion of 5 kinds of chemical reagents, the maximum loss ratio of 0.29% and the maximum decrease of the breaking strength were 5.1%. Mechanical properties and chemical performance of tritium proof polymer composite meet the demand of Protective clothing-protective clothing against liquid acids and alkalis(GB 24540-2009).