Objective To explore the clinical effect of expanded random flap repair surgeryin the treatment of scar after facial and neck burn and its influence on serum index content. Methods A total of 86 patients with facial and neck burn scars admitted to our hospital from December 2022 to December 2023 were selected as the research objects. They were divided into group A and group B by random number table method, with 43 patients in each group. Group A was treated with adjacent flap repairsurgery, and group B was treated with expanded random flap repairsurgery. The scar conditions (VSS, PSAS, OSAS score), serum factor levels and complications were compared between the two groups. Results The scores of OSAS, VSS and PSAS in group B were lower than those in group A at 1 and 3 months after surgery (P <0.05). The levels of VEGF, TGF-β1 and PDGF in group B were higher than those in group A at 1 week after surgery (P <0.05). The incidence of postoperative complications in group B was 9.30%, which was lower than 16.28% in group A, but the difference was not statistically significant (P >0.05). Conclusion The effect of expanded random flap repairsurgery in the treatment of scar after burn of face and neck is better, which can promote the recovery of scar, improve the growth factor level of transplanted flap, and have high safety.