Objective To evaluate the role of aspirin in primary prevention of cardiovascular diseases through a systematic review and meta analysis. Methods Computer retrieval was carried out in PubMed, EMBASE, Cochrane Library, China Biology Medicine disc (CBM), China National Knowledge Infrastructure (CNKI), VIP database and WanFang Data, etc, in December 2014 for the literatures about aspirin, primary prevention, cardiovascular diseases and other search terms. The obtained literatures were screened according to the eligibility criteria. Then the quality of the literature was assessed with methodological evaluation, and the data such as baseline information, methodological characteristics, interventions and outcomes were extracted. According to the heterogeneity test, a fixed-effect model or a random-effects model was selected to perform meta-analysis in each study. Data analysis and charting were done using Stata 11.0 software. Results There were 10 studies incorporated in this study, including 59 365 cases of aspirin group and 57 720 cases of placebo group. The meta-analyses showed the incidence of major adverse cardiovascular events (MACE) was 3.74% (2222 cases) for the former group and 4.00% (2306 cases) for the latter. The results of the fixed-effect model indicated that aspirin reduced the risk of MACE by 10% (RR=0.90,5%CI:0.85-0.96, P<0.000), the risk of myocardial infarction by 16% (RR=0.84, 95%CI:0.72-0.98, P=0.023), the risk of stroke by 6% (RR=0.94,5%CI:0.86-1.04, P=0.211), the risk of all-cause death by 5% (RR=0.94,5%CI:0.90-1.01, P=0.075), and the risk of cardiovascular death by 2% (RR=0.98, 95%CI:0.89-1.09, P=0.776), but increased the risk of hemorrhea by 77% (RR=1.77, 95%CI:1.40-2.22, P=0.000). Conclusion Aspirin is not suitable for primary prevention of cardiovascular diseases, although it can reduce the incidences of MACE and myocardial infarction, but it will increase the risk of hemorrhea.