The work aims to prepare the calcium carbonate (CaCO3) reinforced starch/wood fiber composites and investigate the effect of formula and preparation process on the properties of these composites. Starch/wood fiber composites were prepared by compression molding with CaCO3 as filler, cassava starch as substrate, and wood fiber as reinforcement. Then, the composites were characterized by mechanical and water absorption tests with Fourier transform-infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). When the amount of CaCO3 was 60% (mass fraction) and the molding temperature was 160 ℃, the tensile, flexure and compression properties of the composites were the best, reaching 2.4 MPa, 7.3 MPa and 3.1 MPa, and the elastic modulus reached 985.5 MPa. The characterization by FT-IR, TGA and SEM showed that the composites prepared under these conditions formed more uniform network structures. The CaCO3 reinforced starch/wood fiber composites prepared under the best conditions have excellent mechanical properties, water resistance, thermal stability and biodegradability.