The utility model relates to a photovoltaic power extremum searching system considering the illumination variation. The photovoltaic power extremum searching system considering the illumination variation comprises a photovoltaic panel, a PWM signal generator, a PI regulator, a sensor, a self-adaptation control operator module, a current disturbance operator module and a variable step size disturbance operator module. According to the photovoltaic power extremum searching system considering the illumination variation, the self-adaptation control operator module, the current disturbance operator module and the variable step size disturbance operator module are arranged, the improvement on the perturbation and observation method of the classic amperage is achieved, the photovoltaic power current disturbance volume variable step size disturbance operator module and photovoltaic operating point self-adaptation control operator gel are added, and the rapid and stable operating point adjustment by the photovoltaic power under different illumination conditions is achieved to trace the maximum power. The photovoltaic power extremum searching system considering the illumination variation has the advantages that the structure is simple, the operation is convenient, the problem of oscillating around the maximum power point existing in a traditional perturbation and observation method is solved properly, and the technical problem influencing the stability of the system is solved.