Objective To explore the application scope of small splint in the treatment of type-C distal radius fractures. Methods According to CT scan data from the right forearm of a healthy male volunteer, the three-dimensional model of normal distal radius was established. According to AO classification, the fracture line based on normal model was divided to establish nine kinds of high-order tetrahedral mesh models of the upper forearm with C-type fracture. Finite element analysis on nine kinds of fracture models was conducted in ANSYS 15.0 software to obtain the corresponding stress values, and then the stress distribution contours were generated. Results As soft tissues of the wrist were thin with more fracture blocks, after the splint was fixed, the stress on the wrist under 100 N maximum physiological axial load was significantly larger compared with that on the other parts, and the compressive stress was mainly concentrated on the wrist joint. The fixed effect of C2.2, C2.3, C3.2, C3.3-type fracture by small splint was relatively poor, as such comminuted fracture would cause too many and too small fracture blocks, while the fixed effect of C1.1, C1.2, C1.3, C2.1 and C3.1-type fracture was better. Conclusions Through the related finite element study on the treatment of C-type fracture distal radius with small splint, the application scope of small splint was preliminarily determined, which could provide some reference for clinical work.