First this paper analyzes the model structure and the output characteristics of the photovoltaic (PV) module, and then we get the output characteristic curve using the parameter sheet. In this paper a simple, quick, and low cost Double-line MPPT ( maximum power point tracking) method and an simple temperature compensation method are proposed after analyzing and comparing the cell’s output features in terms of irradiance and temperature environment changes .The detailed process of the theoretical derivation and the simulation in MATLAB are provided. At last, the paper introduces the control strategy of the Double-line MPPT method. We conclude that Double-line MPPT method is Low-Complexity, easier to realize , faster without oscillation compared with other methods ,it can be used in low power PV system.