[Objectives]  To clarify the influence of sex, age (days) and temperature, on the flight ability of adult Hyphantria cunea, and there by provide information essential for monitoring, and predicting, the dispersal of this pest. [Methods]  The effect of gender, age and temperature on the flight ability of adult H. cunea was measured in an insect flight mill. [Results] Males were significantly stronger fliers than females with a maximum flight distance of 17.87 km and cumulative flight time of 17.38 h. One day-old males had the longest cumulative flight distance; the average cumulative flight distance and average cumulative flight time of males decreased with age. The maximum female flight distance was 8.21 km and the longest cumulative flight time was 7.4 h. Female flight distance tended to first increase, then decrease, with age. Three day-old females had the maximum cumulative flight distance. A two-way ANOVA of the average cumulative flight distance, average cumulative flight time, and average flight speed, did not detect a significant interaction between sex and age. Male flight speed was significantly slower at a temperature of 16 ℃. [Conclusion]  Male H. cunea are stronger fliers than females. Male flight ability gradually decreases with age, whereas that of females tends to increase up to 3 days of age, then decrease. Low temperatures reduce the flight speed of H. cunea males.