The swash plate axial piston pump is a typical complex system of electro-hydraulic mixing. Its faults are hardly identified， and a multi-domain simulation modeling method based on actual mechanical structure is on the demand. In this regard， a Modelica-based modeling and simulation approach for the swash plate piston pump is carried out. First， based on the actual mechanical structure parameters of a certain type of piston pumps， component division and assembly modeling are carried out， and a local hydraulic system for the swash plate piston pump is built. Second， common failures of the piston pumps， including leakage， pressure loss， blockage and cavitation， are simulated by the model， and quantitative simulation analysis is carried out. The impact of different faults on the hydraulic system is identified. This demonstrates that the proposed model can work well for the analysis on common faults of piston pumps. This model improves the accuracy of multi-domain unified modeling of swash plate axial piston pumps and provides reference for fault diagnosis and health monitoring.