Abstract：The maximum starting pressure gradient and the nonlinear percolation area distribution are studied based on the low rate non-Darcy flow. From the minimum starting pressure gradient obtained from experiments and the relationship between the starting pressure gradient and the throat radius, the limit shear stress and the maximum starting pressure gradient are obtained. The range of the nonlinear percolation area pressure gradient is determined by using a regression analysis. When the pressure gradient range is related with the pressure gradient distribution, the nonlinear percolation area distribution range can be obtained. Two well group examples show that the nonlinear percolation area distribution range thus obtained is consistent with the oil well dynamics. The method is shown to be practicable. A new method to calculate the limit injection production well spacing is proposed according to the injection production pressure gradient distribution and can be used for calculation of the injection production well spacing in an oilfield development plan.