In China, Populus euphratica forests are not only important for maintaining the ecological balance in Ejina but are also a major tourist attraction. Catocala remissa Staudinger (Lepidoptera Noctuidae) is a defoliator of P. euphratica. In recent years, this insect has been one of the most serious forestry pests in Ejina, Inner Mongolia, China. Currently, chemical insecticides are the only means of control. However, this approach has led to the development of pesticide resistance, which has severe negative impacts on human health and the environment. In order to develop an efficient and pollution-free method of control, we have initiated a series of studies on pest sex pheromones. It is essential to know the mating behavior characteristics and responses of the male to female sex gland extracts. It will provide a basis for extraction, separation, and identification of the sex pheromone. However, studies on sex pheromone-related behavior in C. remissa are yet to be conducted. This study investigates the calling and mating behavior of moths in insect rearing cages under natural conditions in the woods. The responses of the male to female sex gland extracts were studied using an electroantennogram (EAG),wind tunnels, and field tests. Crude extracts of the sex pheromone were prepared by direct extraction of the pheromone from female sexual glands using hexane. The courtship behavior was observed in the dark period and was rhythmic. The females called three days after emergence, and the calling peaked one week later. The calling peak varied with the age of the female and the scotophase time. Females aged 3-4 days called on the 4-6h into the scotophase, with a peak at 6-8 h. Females aged 5-7 days called at the beginning of the scotophase, with a peak at 4-6 h. Responses of males aged 1-10 days to the pheromone extract were monitored using a wind tunnel. Males, aged 3-7 days, showed a significant response to the sex gland extracts. Peak activity was observed in 5-day-old males and at 4-6 h into the scotophase. The mating ability of the moths was examined. Moths aged 3-4 days and 7-8 days exhibited mating behavior 4-6 h and 2-4 h into the scotophase, respectively. Peak mating behavior was observed in 6-day-old and moths 4-8 h into the scotophase. Responses of the male to female sex gland extracts varied with the age of the female and time into the scotophase and were rhythmic. A response was observed to 4-day-old female sex gland extracts, and the response was the highest to extracts of 7-day-old females; this response was significantly higher than those of other aged females (P < 0. 05). The response increased with an increase in the scotophase time, peaking at 5 h into the scotophase. After peaking, the response of the male to female sex gland extracts decreased. Extracts were prepared from females aged 1-10 day to determine the attraction in field trapping tests. The results showed that males were attracted to female sex gland extracts, with a peak at 4-6 h in 7-day-old females. The field trapping test results confirmed that the mating behavior and responses to female sex gland extracts were rhythmic. Therefore, this study enhances our understanding of the chemical communication during the reproductive process and the importance of pheromones in detecting and monitoring this pest in fields.