To examine the flow characteristic of axial piston pump with conical cylinder block, a comprehensive mathematical model of flow condition within a single cylinder bore was developed by utilizing discrete approximation. Each step of the discrete analog was fallen into three successive phases with oil compressibility and classical orifice equation. Besides, the discharge flow equation of whole pump was obtained with lumped parameter method. Based upon this model, a simulation system was built in the simulation software. The novel aspect of this research is that analysis of cylinder block cone angle. From the result of numerical simulation, it can be concluded that cylinder block cone angle has a significant impact on the flow characteristics, and conical cylinder block design is more feasible than cylindrical cylinder block from a flow characteristic point of view.