This paper investigates the effects of temperature and relative humidity on the moisture regain and specific resistance of cotton fibers when a new water-cooled textile air conditioner is used as humidification equipment in the textile production process. Cotton fiber is used as the test object, and the temperature and relative humidity are adjusted to simulate the humidification of the textile production process environment, during which the moisture regain and specific resistance values are measured. The experimental results show that: the time required for cotton fibers to reach the nominal moisture regain shortens with the increase of temperature and relative humidity, and the shortening time is more obvious when the temperature remains unchanged at 75%-80% relative humidity, and the change is obvious at 25 °C-30 °C when the relative humidity is certain. The specific resistance of cotton fiber decreases with the increase of temperature and relative humidity; the specific resistance of the fiber decreases rapidly at the beginning of humidification, and then becomes smaller slowly; with the increase of moisture regain, the specific resistance of fiber decreases in an exponential trend.