Abstract: In order to solve the problems of difficult to control the conductivity and uneven spark in the process of EDM with deionized water as the dielectric, which lead to the poor accuracy of the grinding wheel profile and the flammable and polluting environment in the process of EDM with kerosene as the dielectric, the orthogonal experiment of optimizing the composition of the EDM fluid with deionized water as the matrix is carried out to explore the explosives, lubricants, defoamers and dispersants influence of the proportion and content in the processing fluid on the profile accuracy of the grinding wheel is great; the cross-section profile data of the grinding wheel is collected by the Kearns two-dimensional laser rangefinder, and the data imported by MATLAB is used as the profile peak envelope diagram of the grinding wheel to evaluate the profile accuracy before and after the grinding wheel dressing. The development of ELID grinding in-situ EDM precision machining fluid. The experiment shows that the grinding wheel can reach the precision level of precision forming when the machining fluid with 4% explosive, 0.6% lubricant, 6% defoamer and 3% dispersant is used.