Abstract: Based on theoretical research on grinding force of hard-brittle material in two-dimensional ultrasonic-electrolytic in-process dressing (ELID) composite grinding, the grinding force model of ultrasonic-ELID composite grinding is established.According to the grinding force formula, it is found that grinding force is associated with amplitude and angular frequency of ultrasonic wave.At the same time, grinding force also increases with the decrease of current.Actual grinding force at different grinding depth and wheel speed are compared with those theoretical ones.Resultsshow that both actual and theoretical forces are similar.It is also found that normal and tangential grinding forces increase with the increase of grinding depth or the decrease of wheel speed.