ObjectivesTo systematically review the status quo of studies on the influencing factors of early puberty timing.MethodsWe searched VIP, CNKI, CBM, WanFang Data, PubMed, Ovid, Web of Science, EBSCO and The Cochrane Library to collect studies on the influencing factors of early puberty timing published up to November 16th, 2016. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, quantitative analysis and qualitative synthesis methods were used to analyze the studies.ResultsA total of 146 studies were included, among which 74 were case-control studies. The results showed that: the influencing factors on early puberty timing mainly included 10 aspects: obesity, dietary preference and nutritional intake, environmental endocrine disruptors, genetic, social psychologycal stress, social economic status, lifestyle, intrauterine fetal growth, maternal age at menarche and weight, adverse factors during pregnancy.ConclusionsThe current systematic review showed that obesity, genetic, environmental endocrine disruptors, intrauterine fetal growth and early maternal age at menarche may increase the risk of early puberty timing, while other factors remain controversial. While the definition of early puberty timing and related factors have not been unified, most studies focus on females and qualitative data with lack of in-depth analysis. Therefore high quality cohort studies and studies on males are required.