Abstract: In order to solve the problem that black marks appear in the powder layer on phosphor screen of low-light image intensifier duiring the process of reinforcing, the effects of ratation speed, time, concentration of potassium silicate solution, and temperature on the reinforcement process were explored. As the rotation speed increases, the time is aprropriately prolonged, the concentation potassium silicate solution decreases and the temperature increases, the frequency of balck marks on the powder layer reduces. Based on this, the reinforcement mechanism of powder layer on phosphor screen of low-light image intensifier is proposed, which is mainly the process of centrifugal action overcoming the hydrogen bond between potassium silicate and water molecules. Evaporation is a second factor, but can also be a major factor at high temperature. By weaking the hydrogen bond and improving the reinforcement approaches, the reinforcement yied is significantly improved, which verifies the rationality of the mechanism.