Abstract: Grading is the most preliminary unit operation of post harvest processing and utilization of wild apricot pits.Experiments were designed using response surface methodology where experiments were conducted on pedal operated wild apricot pit grader for optimizing the machine parameters and grading（size basis）operation.Effect of the three independent variables（pedal speed，feed rate and moisture content）of three level each（60，70，80 rmin speed，275，300，375 kgh feed rate and 10.5%，12.5%，14.5%（w.b.）moisture content，respectively）were studied on the grading efficiency（%）and grader capacity（kgh）.Experimental data were analyzed for getting the optimum solutions of the independent variables considered in the study.Full second order model was developed for predicting responses（grading efficiency and grader capacity）and to study the effect of individual parameters and their interactions on the responses.Experimental study revealed that grading efficiency and grader capacity were observed to be in the range of 75.9%～82.4%，and 270～325 kgh，respectively.To be the best performance of the grader for getting maximum grading efficiency and grader capacity，the optimized machine parameters were found to be 75 rmin pedal speed，325 kgh feed rate and 14.5%（w.b.）moisture content of pits.