In order to study the environmental factors that affect spontaneous combustion of coal gangue dump, the influences of season, humidity and wind speed on the spontaneous combustion were analyzed based on the monitored concentration data of CO produced during the spontaneous combustion. The results show that the spontaneous combustion of the coal gangue dump is strong in spring and winter, but gentle in summer and autumn. With the increase of air humidity, the spontaneous combustion experiences a gentle period, an intense period and a gentle period in turn. When the air humidity reaches 32%, the spontaneous combustion is the intensest. With the increase of wind speed, the spontaneous combustion of coal gangue dump experiences an intense period, a gentle period and an intense period in turn. When the wind speed is less than 1.88 m/s or greater than 2.76 m/s, the spontaneous combustion of coal gangue dump is in the intense period. When the wind speed is 1.88~2.76 m/s, the spontaneous combustion is in the gentle period.