Objective To investigate the effects of 3D printing combined with emergency lateral approach surgery on stress response and inflammatory factors in patients with traumatic calcaneal fractures. Methods The research subjects were 126 patients with traumatic calcaneal fractures admitted from February 2021 to February 2024. They were randomly divided into an observation group and a control group using the envelope method, with 63 patients in each group. The control group received emergency lateral approach surgery with traditional X-ray assistance, while the observation group received 3D printing+emergency lateral approach surgery. The differences in serum inflammatory factors, stress indicators, imaging parameters, and ankle joint function at the final follow-up were compared between the two groups. Results Compared with before surgery, the interleukin-6 （IL-6）, C reactive protein （CRP）, tumor necrosis factor-alpha （TNF-α）, and cortisol （Cor） all increased on postoperative day 1, but the increase in the observation group was smaller than that in the control group （P<0.05）. Compared with before surgery, the Bohler angle and Gissane angle significantly increased one week after surgery, and the increase in the observation group was greater than that in the control group （P<0.05）. There was no statistically significant difference in calcaneal width and calcaneal length before and 1 week after surgery （P>0.05）. The calcaneal height of both groups one week after surgery was significantly higher than that before surgery （P<0.05）, but there was no statistical difference between the two groups （P>0.05）. At the final follow-up, the excellent and good rate of ankle joint function in the observation group was significantly higher than that in the control group （P<0.05）. Conclusion The application of 3D printing combined with emergency lateral approach surgery for patients with traumatic calcaneal fractures enables clinicians to become more familiar with the surgical procedure, thereby reducing postoperative inflammatory factors and stress response, and enhancing imaging parameters and ankle joint function.