To establish a finite element model that reflects the geometric characteristics of the normal anterior cruciate ligament (ACL), explore the approaches to model knee joint ligaments and analyze the mechanics of the model. A healthy knee joint specimen was subjected to three-dimensional laser scanning, and then a three-dimensional finite element model for the normal ACL was established using three-dimensional finite element software. Based on the model, the loads of the ACL were simulated to analyze the stress-strain relationship and stress distribution of the ACL. Using the ABAQUS software, a three-dimensional finite element model was established. The whole model contained 22,125 nodes and 46,411 units. In terms of geometric similarity and mesh precision, this model was superior to previous finite element models for the ACL. Through the introduction of material properties, boundary conditions, and loads, finite elements were analyzed and computed successfully. The relationship between overall nodal forces and the displacement of the ACL under anterior loads of the tibia was determined. In addition, the nephogram of the ACL stress spatial distribution was obtained. A vivid, three-dimensional model of the knee joint was established rapidly by using reverse engineering technology and laser scanning. The three-dimensional finite element method can be used for the ACL biomechanics research. The method accurately simulated the ACL stress distribution with the tibia under anterior loads, and the computational results were of clinical significance.