Abstract: In order to provide reference for the design of anaeroic digestor, the expansion characteristics of pig manure and corn stalks with different mixing ratio in the press of anaerobic digestion were discussed in this paper. Under the warm fermentation condition (35℃), the gas characteristics of three animal manure and three corn stalks were tested，and gas generation of 6 typical materials with warm fermentation condition were studied. The results showed that pig manure would expanse in anaerobic digestion, and the higher the dry matter content, the greater the coefficient of expansion. The biogas-producing efficiency of pig manure was the efficiency highest, and the value was 375.5 mL/g(TS). The physicochemical properties of corn stalks with different storage conditions played an important role in gas characteristics, and the no cob silage was the best storage manner, and the gas production was 445.8 mL/g(TS). This research provides a reference for the selection of the materials and optimization of anaerobic digestion.