The grain aphid Sitobion avenae is migratory and seriously infests wheat in China. In this study, flight performances of winged adults of the grain aphid were measured with a 32 channel, computer monitored flight mill system at ten temperatures from 8℃ to 30℃ and three relative humidities (40%, 60%, 80%). The results showed that 12℃～22℃ and 60%～80% RH are suitable for their flight. It was difficult for the aphid to take off at 8℃ and the flight time was shortened significantly. When the humidity increased, the flight time prolonged and the flight distance increased. The flight speed was greater at a RH range of about 60% RH. The maximum flight duration, distance and speed of single aphid were 22.51 h, 14.63 km and 2.05 km/h respectively.