The present invention relates to the field of semiconductor manufacturing, and particularly to a method of making Optical Proximity Correction to an original gate photomask pattern based on different substrate areas. The present invention discloses a method of making OPC to an original gate photomask pattern based on different substrate areas, which makes correction to gate photomask pattern dimension on the AA and to gate photomask pattern dimension on the STI respectively by creating two different optical proximity effect models of the gate, so as to control the finally imaged gate photomask pattern dimensions more accurately; moreover, the error of the correction result of the gate spacing dimension on the STI can be reduced by 4% by separating the patterns and using the gate model based on the STI, so as to avoid the spacing dimension error when the photolithography exposure conditions vary.