In the field of photovoltaic (PV) power generation control, inverter control plays a crucial role. In dual-loop control strategies, linear control methods such as proportional-integral (PI) control are widely used in the outer voltage loop and inner current loop. However, traditional PI and other linear control methods do not consider the nonlinear characteristics of PV inverter systems, resulting in poor dynamic and static performance and robustness. This paper proposes a dual-loop control strategy combining an improved linear active disturbance rejection controller (LADRC) with PI control. To avoid oscillations in the PV inverter system and improve system stability, an improved LADRC is designed by adding an output error compensation term to the linear state error feedback control law, and is applied to the outer voltage loop, while PI control is used in the inner current loop. After parameter tuning and controller performance analysis, it realizes the control on a 1.2 kW single-phase PV inverter system. The system is modelled and simulated in Matlab/Simulink to analyze the influence of the improved LADRC-PI control strategy on single-phase photovoltaic inverter performance. Simulation results show that compared with the traditional dual-loop PI control, the improved LADRC-PI dual-loop control has better system stability, faster response speed, and the improved dynamic and static performance and robustness.