Good balancing is very important to improve the moving performance of grinding machine. General balancing technology of grinders was analyzed. The structure features of a new type of hybrid CNC grinding machine were introduced. The necessity of obtaining good balance of the hybrid grinder was demonstrated. Based on simulation and calculation of the distribution law of potential energy over the grinder, a solution for obtaining partial balance of the machine was worked out. An optimal parameter value of the designed balance unit was reached through optimization calculation with optimal balancing effect as target function. The max actuating force of balanced machine accounts for only 13.7% of the force of un-balanced. The balancing unit is of features of simple structure and good balancing effect.