There is a problem in that it is difficult to balance the steady-state deviation of grid-connected active power with the dynamic oscillation of the system in a traditional PV storage virtual synchronous generator (VSG). Thus a PV storage VSG control strategy based on active power differential compensation (APDC) and virtual inertia adaptive strategy is proposed. First, a closed-loop small signal model of a PV energy storage VSG based on the APDC algorithm is established, and the suppression effect of the algorithm on transient oscillation and steady-state deviation of active power is determined by analyzing a pole map and Bode diagram, and the tuning method of correlation coefficient is given. Then, to improve the frequency response performance and avoid the increase of active power overshoot, an improved virtual inertia adaptive strategy based on the APDC algorithm is designed, and the range of its parameters is given. Finally, experimental results show that the proposed strategy can eliminate the dynamic oscillation and steady-state deviation of the VSG grid-connected active power, with smaller frequency deviation and change rate.