An analog integrated maximum power point tracking (MPPT) controller which is suitable for distributed MPPT (DMPPT) topology is presented in this paper. Without large numbers of external circuit components, the DC/DC converter together with its MPPT controller can be made small enough to be integrated into the junction box, which is practical and cost effective for DMPPT topology. Besides a negative feedback loop is used in the proposed system to make the output voltage of PV panel less susceptible to fluctuations of irradiation intensity and interference of switching noise. Meanwhile, an improved P&O algorithm is adopted to achieve a fast and precise tracking especially in fast changing weather conditions. Furthermore, the tracking precision is higher than 99.5% under different external environmental conditions.