Abstract: Mating behaviors of Campoletis chlorideae and affecting factors were investigated in laboratory. Results indicated that male adults played dominant role in mating. Male adult copulated more than one time while female usually copulated just one time in their lifetime. Successful copulation was the highest in 24 h and 36 h old female and, 36 h old male among all the adults tested, and suitable temperature and light intensity for successful copulation were 25-35℃ and 1500 lx, respectively. It was suggested that indoor environmental condition were important factors responsible for offspring male bias.