摘要： this paper deals the performance comparison and efficiencies of single-axis and dual-axis tracking PV system to an identical fixed-mount PV system for two typical clear sunny days (Ghardaia area), two typical days are chosen, the first day in winter and the second day in the summer. For the three types of PV systems, P&O-PI MPPT techniques optimized with a genetic algorithm is proposed. This paper has two different objectives. 1stly, a proposed MPPT technique has been presented to optimize P&O-PI controller via the GA technique to increase the tracking response of MPP with high efficiency and that improves the limitations of the traditional MPPT techniques. 2ndly, a performance comparison of efficiencies of single-axis and dual-axis tracking system and an identical fixed inclination system .Simulation results with MATLAB/SIMULINK are presented and discussed to verify the satisfactory performance of the proposed MPPT control, in which the optimized P&O-PI controller by GA algorithms gives the better performance. The simulation results also have shown that both single-axis and dual-axis are highly efficient in terms of the electrical energy output when compared to the fixed mount system. The results show the effectiveness of the tracking system of about 25% in energy efficiency.