Abstract: OBJECTIVE To explore the mechanism of electroacupuncture at different points combination in the treatment of rats with functional constipation (FC). METHODS SD rats replicated by intragastric administration with 0 ℃ 0.9% sodium chloride solution were taken as FC animal model and randomly divided into model group， electroacupuncture group Ⅰ， electroacupuncture group Ⅱ and electroacupuncture group Ⅲ， SD rats were taken as control group. EAⅠhad electroacupuncture at bilateral Tianshu(ST 25)， Dachangshu(BL 25)， EAⅡ had electroacupuncture at bilateral Quchi(LI 11)， Shangjuxu(ST 37)， EAⅢ had electroacupuncture at unilateral Tianshu(ST 25)， Dachangshu(BL 25)， Quchi(LI 11)， Shangjuxu(ST 37). Observation on fecal characteristics and intestinal carbon propelling rate were used to evaluate intestinal motility of rats， transmission electron microscopy was used to observe colonic mucosa ultrastructure of rats， Western blot was used to determine the protein expression of AQP3， AQP8 in colon of rats， qPCR was used to determine the mRNA expression of AQP3， AQP8 in colon of rats. RESULTS The number of 24 h fecal grains， 24 h fecal water content and intestinal carbon propelling rate in EA Ⅱ group increased significantly(P<0.05)， protein and mRNA expression of AQP3， AQP8 in the model group was significantly higher than that of normal group in colon of rats， while significantly reduced after treatment with EA Ⅱ(P<0.05)， the ultrastructure of colonic mucosa were significantly improved after treatment with EA Ⅱ. CONCLUSION The mechanism of electroacupuncturestimulating Quchi(LI 11)， Shangjuxu(ST 37) on enhancing intestinal motility and improving the symptoms of constipation may be due to the reducing the expression of AQP3， AQP8 protein and AQP3， AQP8 mRNA in colonic mucosa of FC rats， thus reducing water reabsorption of colon， increasing fecal water content in colon， regulating water transport and improving the ultrastructure of colonic mucosa.