Abstract:Abstracts:The study described the copulation and avoiding inbreeding of a provisioned group of Sichuan snub nosed monkeys (Rhinopithecus roxellana). Using behavior sampling and all occurrence recording method, copulation were recorded for a group of 45 individuals in Shennongjia Nature Reserve from April to November 2008.The results indicated that the initiators of prostrating behavior exhibited significant differences among sex classes, females initiated prostrating behavior more frequently than males. The frequencies of successful copulation among females of initiators were adult,next was young,The last was juvenile. There were four types of interfering behaviors during copulation course, and significant differences among different interfering behaviors. Females exhibited multiple prostrating behavior,this may enlarge successful percentage of prostrating behavior. Low successful copulation rate indicated that the function of copulation was not only reproduction.