This paper investigates the influence of lattice structures on the mechanical properties of 3D-printed structures using Polylactic Acid (PLA) biodegradable plastic. The study utilizes a cubic model with dimensions of 50 × 50 × 50mm as the test model, featuring three different lattice structure types. The typical lattice structures include a triangular lattice with an inclination angle of (-30/30), a square lattice with an inclination angle of (0/90), and a square lattice with an inclination angle of (-45/45). The mechanical properties of these models are predicted through simulations and validated with high reliability through experiments. The research results indicate that the triangular lattice pattern exhibits superior mechanical properties compared to the other patterns, attributed to better connectivity and force distribution among the struts. The study underscores the significance of lattice structure in 3D printing as a critical factor significantly influencing the mechanical properties of 3D-printed structures.