Objective To study the preparation technology of paper mill sludge / polyvinyl chloride ( PVC) wood plastic composites ( WPC) . Methods The WPC were prepared by hot press molding technology with paper mill sludge as reinforced material and PVC as plastics matrix, and the effects of paper mill sludge content, hot pressing time, temperature, pressure, and dosage of coupling agent on the mechanical properties of the composites were investigated, respectively. In addition, the composites and paper mill sludge were characterized by scanning electron microscope ( SEM) and Fourier transform infrared spectroscopy ( FT-IR) , respectively. Results Under the conditions of a paper mill sludge content of 50% , a weight percent of coupling agent / paper mill sludge of 2% , a hot pressing time of 10 min, a temperature of 180 ℃ , and a pressure of 6 MPa, the bending strength and tensile strength of the paper mill sludge / PVC composite were 35. 73 MPa and 12. 75 MPa, respectively, indicating the favorable mechanical properties of the composite. SEM analysis showed that the interfacial compatibility of the composite prepared by silane coupling agent-modified paper mill sludge and PVC was significantly improved, resulting in the enhancement of its mechanical properties. FT- IR analysis indicated that crosslinking reaction had occurred between the coupling agent and the paper mill sludge, forming chemical bonding. Conclusion It is feasible to prepare WPC with the blend of paper mill sludge and PVC.