Abstract: 578 rhesus infants were separated from breeding females before mating season and were used for nursery rearing experiment at Xishuangbanna,Yunnan National Laboratory Primate Center of China (YNLPCC) during 1984-1988.The weaning age varies from 1 to 230 days after birth,with an average of 113 days.91.5% of infants were survival in the first rearing year.In the infants died within the first rearing year,61.8% of them occurred in the first mont;the death rate of infants weaned age under two month old (≤60 days) was 20% and which of weaned age over two month old was 6.9%.64.7% of death were resulted from pneumonia and enteropathies.The nursery-rearing infants of male under ten months of age and female under nine months of age have a rapid growth rate,their regressive equation on the growth of body weight (grams) are:W=145.6t+403.5 (male,under 10 months of age);W=144.2t+372(female,under 9 months of age).We believe that separating infants from their mothers before mating season could improved female fertility.