To investigate the effect of photodynamic therapy combined with compound betamethasone in the treatment of hypertrophic scar.37 cases of keloid were divided into two groups, 19 cases in the treatment group, 18 cases in the control group. The patients in treatment group were treated with photodynamic therapy combined with compound betamethasone injection therapy. The patients in the control group were treated by compound betamethasone injection. The effect and recurrence rate were compared before and after treatment.The effective rate was 89.5% in the treatment group, 55. 6% in the control group, showing significant difference between the two groups (P = 0.029) The relapse rate in treatment group was significantly lower than that in the control group (P = 0.047) CONCLUSIONS: Photodynamic therapy combined with compound betamethasone has good effect and safety for the treatment of hypertrophic scar. The combined treatment can reduce the treatment period and side effects