In this study, composite films were prepared with Konjac glucomannan (KGM) and Starch, In the process of preparation, add Lactic acid as modifier, deal with Ammonia as crosslinker. Pretreatment with microwave, and used solvent (water) casting method to prepare the KGM/starch composite films, and used orthogonal matrix L25 (5,6) to analyze the influencing factors. The results showed that: the tensile strength of films is 7.96~25.68Mpa, and the fracture elongation rate is 1.25~5.00%. It can reach the tensile strength requirements of films for food packaging materials (polyethylene films) and the optimal level is A2B4C3D3. By XRD analysis, KGM/starch composite films showed amorphous. Preliminary degradation experiments shows that the decomposition period of KGM/starch composite films is 2 weeks in the soil suspension. Therefore, KGM/starch composite films are potential biodegradable film materials.