[Objectives]  To determine the effects of temperature and relative humidity on the flight capacity of Exorista civilis Rondani, a potential biological control for Loxostege sticticalis L., an important pest of natural and artificial grasslands in northern China. [Methods]  A flight-mill system was used to measure the flight capacity of E. civilis under different temperature and humidity conditions. [Results]  The optimal flight temperature was 21℃, at which the flight distance, flight time and average flight speed were 5.4543 km, 2.7392 h and 2.2469 km/h, respectively. The optimal flight humidity was 40% RH, at which the flight distance, flight time, average flight speed were 5.7043 km, 2.6594 h and 1.8327 km/h, respectively. [Conclusion]  The flight capacity of E. civilis peaked at 21℃, after which it decreased with increasing temperature. The optimal flight capacity of E. civilis occurred at a relative humidity of 40%. There was no significant difference between the flight capacity of males and females.