© 2021, ASM International.In this study, the surface properties of a model part produced from poly lactic acid (PLA) using 3D printing were improved. For this purpose, tensile and bending test samples were produced and composite coating reinforced with marble/alumina was applied on the specimens. Then, the PLA and coating interface were examined under SEM for adhesion. Besides, the surface hardness was measured, and tensile/bending tests were performed to investigate mechanical properties. In the optimum conditions obtained as a result of the tests, the composite coating was applied to a model part. As a result of the study, the composite coating was successfully applied to a model part produced via 3D printing in a practical way. Surface properties such as roughness and hardness have been improved thanks to the composite coating. Higher values were obtained in terms of tensile, bending, and adhesion strength with samples using marble powder. However, a harder surface was obtained with alumina-reinforced composite coating (90 Shore D) according to PLA that is a significant gain for surface wear resistance. In SEM images, it was observed that there was no separation at the interface, and the coating adhered well to the PLA surface. Adhesion strengths between PLA and coating were 8.2 MPa with marble and 5.3 MPa with alumina.