Abstract: In order to determine the operation parameters, use delinted cottonseeds dielectric selection, three parameters, namely, separation voltage, roller rotatation speed and the cotton seed moisture were selected as input variables, and the dielectric constant, cotton seed vigour and its index selected after the dielectric selection of the cotton seed as output parameters. A quadratic regression general experimental design was employed to develop the second order polynomial regression model, which explained the relationship between input and output parameters. An optimum combination of input parameters was obtained with the region of separation voltage 6 000.00–6 574.43 V, roller rotatation speed 30.08–34.38 r/min and the cotton seed moisture of 4%. Those are useful references for cottonseed delinting by dielectric selection.