To analyze the effect of composite skin grafe and skin soft tissue expansion in the treatment of burns and plastic surgery. Methods From January 2017 to December 2022, 80 patients treated for burn and plastic surgery in our hospital were selected as the research objects. They were divided into reference group and analysis group by random number table method, with 40 patients in each group. The reference group was treated with composite skin grafe, and the analysis group was treated with skin soft tissue expansion. The wound outcome indexes, clinical efficacy and complications were compared between the two groups after treatment. Results The recovery time of skin blood supply and wound healing time in the analysis group were shorter than those in the reference group, and the differences were statistically significant (P <0.05). The total effective rate of treatment in the analysis group was 95.00%, which was higher than 77.50% in the reference group, and the difference was statistically significant (P <0.05). The incidence of complications in the analysis group was 5.00%, which was lower than 20.00% in the reference group, and the difference was statistically significant (P <0.05). Conclusion Skin soft tissue expansion in the treatment of burn and plastic surgery is helpful to improve the clinical efficacy, effectively shorten the recovery time of wound symptoms and reduce the incidence of complications, which is worthy of dinical application.