Objective To analyze the effect of 3D printing assisted by double plate in the treatment of patients with complex tibial plateau fractures. Methods The clinical data of 105 patients with complex tibial plateau fracture admitted to our hospital from September 2019 to September 2022 were retrospectively analyzed, and they were divided into control group (47 cases) and auxiliary group (58 cases) according to different treatment methods. The control group was treated with traditional plate internal fixation, and the auxiliary group was given 3D printing before bilateral plate internal fixation. The average follow-up period was 20.15 months (12-48 months). The clinical efficacy, Lysholm score, Rasmussen satisfaction score for fracture reduction and knee range of motion (ROM) were observed and compared between the two groups before and after treatment, and adverse reactions were recorded. Results The total effective rate of the adjuvant group was higher than that of the control group (96. 55% vs 82. 98%, P＜0.05). After treatment, the recovery time of each item in the auxiliary group was lower than that in the control group ［(67.23±8.10) min vs (103.24±12.14) min,(12.19±1.54) min vs(15.66±2.35) min,(151.29±17.48) mL vs (250.37±27.16) mL］(P＜0.05); there was no difference in Lysholm score of knee joint between the two groups (P＞0.05). The Rasmussen scores of the two groups were increased 3 and 6 months after treatment (P＜0.05), and the scores of the auxiliary group were higher than those of the control group (21.25±3.23) vs (18.49±2.71),(27.66±3.53) vs (23.24±3.15))(P＜0.05). After 3 months of treatment and at the last follow-up, the range of motion of joints in both groups increased (P＜0.05), and the auxiliary group was higher than the control group ［(94.35±10.66)°vs (89.35±10.01)°,(118.21±18.54)°vs(111.08±12.36)°］ (P＜0.05). Conclusion 3D printing assisted treatment for patients with complex fractures of the plateau of the shin helps to recover the knee joint after fracture surgery and achieve higher satisfaction with fracture reduction. It could be used as an ideal method to treat complex fractures of the plateau of the shin