To evaluate the effects of provisioning on affiliative behaviors of Sichuan Snub-nosed Monkeys(Rhinopithecus roxellana),we conducted a systematic observation on a group in the Shennongjia National Nature Reserve from January to September 2007 by using behavior sampling,scanning sampling and all-occurrence recording methods.The group consisted of 3 one-male units(OMU)and 1 all-male unit(AMU)with 45 individuals in total.Eleven types of affiliative behaviors were defined and recorded.Allo-grooming,opening mouth,embracing,playing,and approaching occurred more frequently than others.No significant difference in affiliative behaviors between gender was found for initiators and recipients,but significant difference existed for initiators between age classes in the OMU(in descending order):adults,juveniles,the young,and sub-adults;while within the AMU,the frequency order was adults,juveniles,sub-adults,and the young.Individuals within an OMU exhibited more affiliative behaviors than those between OMUs.However,behaviors such as holding waist,squeezing into,opening mouth,and kissing back only performed by individuals within the same OMU.These results indicate that members in OMUs are closer to each other than individuals between OMUs be.Each OMU might be,to some extent,a socially integrated unit.No difference was found in frequency of affiliative behaviors occurred in breeding and nonbreeding season.