To improve the vehicle fuel economy and prolong the thermal fatigue life of the traditional shock absorbers, energy regenerative electromagnetic shock absorbers have attracted wide attentions. This paper discusses a hydraulic electromagnetic shock absorber (HESA), which has high reliability. A dynamic model of HESA is created in this paper, which shows that the damping force of HESA is composed of the electric damping force, friction damping force, the inerter force and the accumulator force. Influences of hydraulic motor and pipe diameter on the force are analyzed based on the modeling. The parameters of the nonlinear component accumulator are also studied experimentally. Both modeling and lab tests show that the accumulator force can counteract part of the effect of the inerter force, which is greatly beneficial for the vehicles. The damping characteristics and energy harvesting characteristics are also studied based on the lab tests. Results show that the damping coefficient of HESA ranges from 12000Ns/m to 92000Ns/m at a vibration input of 3Hz frequency and 5mm amplitude, and HESA has a unique damping characteristic which needs to be further studied for vehicle dynamics. In addition, the efficiency of HESA can achieve 30% at a vibration input of 3Hz frequency and 7mm amplitude with external resistance of 4 ohms. The average power at this excitation can reach 102 watts.