Abstract:During the process of digitalizing the well logging graphs, in order to avoid the disturbance of automatic curve tracing caused by the coordinate grids, the coordinate grids should be deleted before tracing.To delete them effectively,a new method based on frequency domain filter was proposed, which is called as ‘+ shape and low pass filter’ method. First the ‘+ shape filter’ was used to get rid of the vertical and horizontal edges. Then the low pass filter was used to get rid of the rest of the grids, and a method was proposed to determine the filter radius automatically. The new method was proved to be effective to remove the even grids by the experiments,which provides a reference to research on deleting the grids in frequency domain.