Objective To investigate the clinical effect of ultrasound-guided acupotomy at myofascial trigger points in the treatment of lumbodorsal myofascial pain syndrome (MPS). Methods A total of 60 patients with lumbodorsal MPS were randomly divided into ultrasound group and conventional group, with 30 patients in each group.The patients in the conventional group were treated with conventional acupotomy, and those in the ultrasound group were treated with ultrasound-guided acupotomy,once every week,with four consecutive treatment sessions as one course.Short-form McGill pain questionnaire (SF-MPQ) was used to evaluate the degree of pain before and after treatment,the Youngs modulus value of multifidus muscle was used to evaluate the changes in muscle status,and clinical outcome was observed for both groups after treatment.Results After treatment,both groups had significant reductions in SF-MPQ score and Young's modulus value (P<0.05),and compared with the conventional group,the ultrasound group had significantly greater reductions in SF-MPQ score and Youngs modulus value (P<0.05).The ultrasound group had a significantly better clinical outcome than the conventional group (P<0.05).Conclusion In the treatment of patients with lumbodorsal MPS,ultrasound-guided acupotomy at myofascial trigger points can significantly alleviate pain and improve muscle elasticity.