Electrochemical machining (ECM) is an advanced machining process belonging to electrochemical category. Where in the material removal takes place by anodic dissolution of work piece in an electrolytic solution. This research presents results of the Electrochemical Machining (ECM) process, which was used to remove metal from the internal hole of the work piece (pure Zinc) by brass tool in an aqueous solution NaCl solution. The experimental study the effect of (ECM) process parameters such as (Current density, Gap distance, Electrolyte concentration) on Metal Removal Rate (MRR) and particle size of (Zinc oxide) sludge waste that precipitate from ECM. X-ray diffraction pattern for the resultant powder shows well-crystallized Zinc oxide powder The results indicated that particle size decreases from (82.432 to 24.6μm) and enhancement of MRR by (58.15%) with increasing current density. The increasing in gap distance between tool and work piece from (0.5 to 1.5) mm causes increasing in particle size from (76.451 to 91.81) μm and decrease (MRR) to (11.07%). For electrolyte concentration increasing from (100 to 300 g/l) leads to decrease in particle size from (89.218 to 32.406) μm, while improvement in MRR by (4.83%).