Linear conjugated internal gear pumps are widely used in eletro-hydrostatic actuating systems as power elements with their efficient and low-noise performance. A linear conjugated internal gear pump simulation model was established by the lumped parameter method, the fluid domain within a linear conjugated internal gear pump can be specified as a finite number of volumes where the fluid properties (e.g, pressure, density, and modulus of elasticity, etc.) can be considered as concentrated variables. A test platform was constructed to measure the suction and discharge pressure pulsations of the linear conjugated internal gear pump. The excitation sources, including the pressure pulsation in the inlet and outlet ports, the pressure in the tooth cavity, and the radial force of the gear and tooth ring in the x and y directions were calculated and analyzed. The results demonstrated that the lumped parameter model of linear conjugate internal gear pump established had good accuracy and reliability. The magnitude of the radial force on the gear and tooth ring varied periodically with the deflection angle. In the x direction, the radial force acting on the tooth ring was pointed to the low-pressure side, and the radial force acting on the gear was pointed to the high-pressure side. In the y direction, both theradial forces acting on the gear and ring were fluctuated between positive and negative values. The radial forces in the x direction were smaller than those in the y direction at the fundamental harmonic;the phenomenon of oil trapping led to a slight increase in the pressure in the tooth cavities. The research result can provide a reference for the optimized design and vibration noise analysis of linear conjugated internal gear pumps.