Abstract: OBJECTIVE To discuss the basic factors influencing curative effects of Gua Sha (at acupoints or along meridians) and explore relations of curative effects with site and strength. METHODS 210 patients with lumbar muscle strain were divided into 5 groups with 42 cases in each group， namely the group of Gua Sha at acupoints with ecchymosis， the group of Gua Sha therapy along channels with ecchymosis， the group of Gua Sha at acupoints without ecchymosis， the group of Gua Sha therapy along channels without ecchymosis and the group of acupuncture. The 5 groups were treated for 7 times successively. VAS scores， ODI scores and curative effects of the 5 groups were recorded before and after each treatment and during follow-up visits which were one month and three months after treatment. RESULTS VAS scores and ODI scores of the 5 groups after treatment were obviously improved (P<0.01) and the curative effects were reliable during follow-up visits one month and three months after treatment and the group of Gua Sha therapy along channels with ecchymosis had the best curative effect(89.7%). The ecchymosis and scraping sites are the main influential factors of curative effects by Logistic stepwise regression analysis. CONCLUSION Gua Sha therapy has significant effects on the symptoms of lumbago. The ecchymosis and manipulating Gua Sha therapy along channel are the main factors affecting the corresponding curative effects.