Objective Observing and analyzing the delivery behaviour of cynomolgus macaques, to establish the criteria for determining the occurrence of delivery in cynomolgus macaques, and then combining with veterinary assistance in order to improve the live birth rate of cynomolgus macaques.Methods By backtracking and analyzing the surveillance videos of 112 perinatal cynomolgus macaques with a gestation period of 140 d or more from 2017 to 2021, we observed and recorded the main behavioural manifestations of the cynomolgus macaques during labour, including Valsalva's maneuver, touching and licking the birth canal, lying on their backs or stomachs, and rolling and tumbling of the body. On this basis, we established the weights of delivery-related behavioural indicators and exhaustively analysed the perinatal behavioural performances of 30 cynomolgus macaques for delivery determination.Results The perinatal behavioural validation results of the 30 cynomolgus macaques showed that the behavioural indicators of Valsalva's