This paper presents the numerical elastic solution for a real problem, functionally graded chamber of hydraulic gear pumps under internal pressure. Because of the similarity and complexity for the considering geometry, a bipolar cylindrical coordinate system is used to extract the governing equations. The material properties are considered to vary along the two tangled circles with a power-law function. The two coupled governing equations solved by the differential quadrature method. The results are presented for various material index and show that the complexity in considering geometry and material inhomogeneity can change the stress and displacements value through the geometry efficiently. The results and presented method in this paper for extracting and solving the problem can be used for designing similar geometry more accurate. The results of this research are compared with those reported in the previous work.