Based on orbital drilling machining principle, the theoretical calculation model and formula for residual height of hole wall were established, and simulation model of hole wall microstructure was constructed from them. In both cases that the ratio of tool rotation speed and revolution speed were integer and noninteger, morphology simulation and test of hole drilling were conducted respectively for getting the change law of effects of cutting control parameters on orbital drilling roughness. Morphology simulation results show that when the ratio of rotation speed and revolution speed is an integer, hole wall roughness decreases with the increase of tool teeth and self rotation speed. Following the increase of revolution speed and revolution radius, hole wall roughness increases. Meanwhile, axial feed pitch has no significant effects on hole wall roughness. When the ratio of rotation speed and revolution speed is a noninteger, the analysis of test results show that under the same revolution radius, hole wall roughness shows increasing trend when rotation speed, tangential feed per tooth, and axial feed pitch increases, among which the influence of rotation speed and axial feed pitch is more remarkable than tangential feed per tooth. When machining under different revolution radius, the increase of revolution radius helps rotation speed, tangential feed and axial feed pitch, decrease hole wall roughness.