Objective To observe the effects of tanshinone applied to SD rats expanded prefabricated flap for itself scalded scarring restitution, and investigate the mechanism of pharmacal action. Methods Forty SD rats were used to make the scalded model added to prefabricated neck expanded axial flap for itself. Ten successful SD rat models were selected randomly as intervention group that implemented with transplanted flap scar repairing and drenched tanshinone capsule. The other 10 SD rat models were selected as blank control group with scar repairing and placebo. On the postoperative day 7, the same size of 1 cm2 transplanting skin flap of each rat was cut and embedded with paraffin. Two-step immunohistochemical technique was used to detect the expressed level of superoxide dismutase (SOD) and vascular endothelial growth factor (VEGF) protein that were determined and compared by computer image semi-quantitative method. Results Twenty-five SD rat models were achieved, and 10 rats were selected in intervention group and control group respectively. The animals in both groups were implemented with transplanted flap for scar repairing successfully. The survival rate of the transplanted flap in the tanshinone intervention group was higher (P=0.021), and the expression levels of SOD and VEGF protein were both higher than those in the control group (P=0.003, P=0.005). Conclusion Tanshinone can improve the effects of scar reconstruction and repairing with expanded skin flap of scalded rats and the mechanism may be due to the increased expression of SOD and VEGF protein in the transplanted skin. Key words: Prefabricated expanded flap; Superoxide dismutase; Vascular endothelial growth factor; Scar restitution