Objective: to discuss the effect of CO2 fractional laser assisted with ultrasonic basic fibroblast growth factor(bFGF) delivery on acne scars and its influence on adverse reactions. Methods: 79 cases of patients with acne scars in our hospital from January 2016 to February 2019 were analyzed retrospectively, according to the different treatment methods, the patients were divided into the control group (n=43, CO2 fractional laser treatment) and the study group (n=36, CO2 fractional laser treatment + ultrasonic bFGF delivery treatment). The clinical efficacy of the two groups was compared, and the wound healing time, erythema duration, time of missed work, incidence of adverse reactions, comfort and appearance satisfaction of the patients in the two groups were recorded. The scar ECCA score, erythema index, melanin index, transepidermal water loss (TEWL) and cuticle moisture content before and after treatment in the two groups were observed.Results: ①The total effective rate in the study group was 91.67% (33/36), higher than that in the control group (79.07%(34/43), but the difference was not statistically significant (P>0.05).②The wound healing time, duration of erythema and time of missed work in the study group were shorter than those in the control group, and the incidence of adverse reactions was lower than that in the control group, with statistically significant differences (P<0.05).The comfort degree and satisfaction degree of the patients were higher than those of the control group (P<0.05).③ECCA score , erythema index, melanin index,TEWL,water content of cuticle were no statistical difference (P>0.05) before treatment between the two groups, ECCA score, erythema index, the index of melanin TEWL significantly decreased (P<0.05) and cuticle moisture content significantly increased (P<0.05) after treatment in the two groups, but the improvement of ECCA score, melanin index, TEWL and cuticle moisture content in the study group was greater than that of the control group (P<0.05).Conclusion :Ultrasonic bFGF delivery can improve the efficacy of CO2 fractional laser in the treatment of acne scars and reduce adverse reactions.