Objective To observe the effects of ultrasound-guided serratus anterior plane block(SAPB)for pain relief in the acute phase of rib fractures and its impact on early rehabilitation.Methods This study included 160 patients from Taizhou Central Hospital with unilateral rib fractures undergoing conservative treatment.The patients were randomly divided into two groups,with 80 patients in each group.Group A received flurbiprofen alone for pain relief,while Group B received ultrasound-guided SAPB combined with flurbiprofen.Numerical rating scale(NRS)before treatment and at 1h,6h,12h,24h,and 48h after treatment,additional analgesic use,adverse reactions,functional recovery parameters(including vital capacity,peak expiratory flow,and walking distance),and hospital stay duration were recorded and compared between the two groups.Results The pain scores in Group B were significantly lower than those in Group A at 1h,6h,and 12h after treatment(P＜0.01),with no significant differences at 24h and 48h(P＞0.05).The use of additional analgesics and adverse reactions were significantly less in Group B compared to Group A(P＜0.01).Group B patients had significantly higher vital capacity,peak expiratory flow,and walking distance(P＜0.01).Additionally,the average hospital stay in Group B was significantly shorter than that in Group A(P＜0.01).Conclusion Ultrasound-guided SAPB combined with flurbiprofen is significantly more effective than flurbiprofen alone for treating rib fracture patients.SAPB provides more effective pain control,faster functional recovery,and has a high safety profile.