According to the requirements of the physical characteristics,the manufactural process and the manufactural safety for the powders,the capacitor method was selected on the basis of the comparison and analysis for all kinds of the methods for the on-line moisture-bearing powders. The experimental research was carried out for the powder of moisture content from 8% to 20% under different temperatures(100 ℃,150 ℃,200 ℃,250 ℃). Results show that the powder weight of the given capacity is monotonic decreasing and the powder capacitance is monotonic increasing while the moisture content is increasing. Therefore,the capacitor method for the moisture content powder has high sensitivity and the on-line testing technique is feasible. Finally,some manufactural suggestions for the engineering equipments were put forward.