Abstract: A new method of computation of the pressure gradient force for high and steep topographic areas is developed and named as error subtraction method. The basic principle of the method,which is simple and accurate,is given. Later, ideal atmospheres and three approximate formulas for computation of pressure gradient force are used to check the method. Results show that all of the three methods are not precise enough when they are directly used in computation. In areas with steep slopes the relative errors of the three formulas can reach 20% or above. Even in plain areas with small and low topography,the relative errors are still not negligible.Only the format using average temperature is satisfactory. However,when the three formulas are used in the error subtraction method,the absolute and the relative errors are remarkably reduced, the orders of the relative errors are around 10^-2.