Abstract: Composite insulators are important components of transmission line external insulation, and their surfaces will be stained by contamination continuously until reaching saturation. In order to study the effects of factors such as electric force, drag force and capillary force on contamination saturation characteristics on insulator surface in the rainless environment quantitatively, we designed an insulator saturation contamination test platform independently. The platform utilizes field-charging method to control charge-mass-ratio of particles, aiming to control the electric field force on particles and accelerate the saturated fouling process. Meanwhile, the fan was used to create windy environment in the contamination region so as to ensure the constant temperature and relative humidity of experiments in the artificial climate chamber. By utilizing the platform to launch the saturation tests, we obtained contamination characteristic curves of composite insulators under different voltage levels, voltage types, contamination particle sizes, wind speeds and relative humidity, which were further verified in the wind tunnel test system. The test results show that except for wind speed and relative humidity, the other factors only affect the contamination accumulation speed but not change the saturated contamination quality. The promoting effect of small size particles on contamination accumulation is more significant when the charge-mass-ratio is low. The saturated contamination quality and contamination accumulation speed will decline with the increasing of wind speed and increase with the increasing of relative humidity. The research results can be employed to provide reference for establishing scientific and reasonable insulation cleaning system.