It has obvious strengths of Electrical-discharge Machining (EDM) dressing diamond grinding wheel. In order to improve the dressing efficiency, the influence of the electrical parameters on the dressing of the efficiency was studied. The experimental process was designed by using variablecontrolling approach. The special Computer Numercial Control (CNC) machine tool was used as the experimental machine tool. Because of the tiny removed quantity, two methods were used as measuring the removal thickness and measuring the removal quality at the same time. The two methods could be proved each other, which could confirm the measurement accuracy. Experimental results show: in a certain range, increasing the power of the pulse power supply can increase the dressing efficiency; in a certain range, increasing the pulse interval can improve the dressing efficiency on the contrary. The results can provide reference for improving the efficiency of the EDM dressing diamond grinding wheel.