Objectives : This review is to summarize and assess the effects of acupuncture on parasympathetic nervous system(PNS). Methods and Materials : We searched two electronic databases (CNKI, PubMed) for the articles published until Oct. 2010. The randomized clinical trials (RCTs) and uncontrolled clinical trials (UCTs) were considered to be reviewed. We selected four RCTs, seven UCTs and one article which conducted both RCT and UCT, and reviewed them. The quality of RCTs was also assessed with Cochrane criteria. Results : There were four RCTs which reported acupuncture enhanced PNS, and one RCT reported acupuncture reduced PNS. Four UCTs reported acupuncture enhanced PNS, three UCTs reported acupuncture reduced PNS and one UCT reported there was no remarkable change of PNS after acupuncture. Conclusions : Although the majority of reviewed articles showed acupuncture enhance PNS, it is hard to conclude clearly how acupuncture affects PNS due to insufficient quality of trials. Therefore, more trials with strict condition need to be conducted to obviously identify the effects of acupuncture on PNS.