Abstract: The results of a field experiment show that the wheat straw,mulch film,sorghum straw mat,and cardboard as mulch materials can preserve the soil moisture and especially increase the soil moisture in the upper layer (0～10cm in depth).Mulch film also has a high capacity for increasing the soil temperature,but the soil temperatures in the fields mulched with straw,mat,and cardboard are lower than those of control.All the mulch materials but cardboard increase the quantities of bacteria,fungus,and actinomyces in soil in varying degress.Microorganisms are the highest in the quantity in the soil mulched with straw.Straw,mulch film,and mat mulching treatments significantly increase the height,stem diameter,and leaf area index of corn plant.The mulch materials also have some influences on the net photosynthetic rate of corn plant in the earlier stages of its growth and development.Straw,mulch film,mat,and cardboard mulching treatments increase the corn yield by 19.4%,17.2%,16.1%,and 13.3% respectively.The direct reason of the mulch materials increasing the corn yields is mainly because of the increases of ear length and grains per ear.