Abstract: Since the voltage and reactive power optimization model of distribution network with distributed photovoltaic（PV）is a typical non convex mixed integer nonlinear optimization model,this paper proposes an improved alternating direction multiplier method（ADMM）to solve the voltage and reactive power optimization problem of distribution network with distributed photovoltaic. Taking on load tap changer and switched capacitor bank as examples,a new generalized decomposable voltage and reactive power optimization model of active distribution network with distributed photovoltaic is established. Then,the voltage and reactive power optimization model of distribution network with distributed photovoltaic is decomposed into two subproblems to solve according to ADMM algorithm,and a self-adaptive adjustment mechanism of penalty parameters is designed to accelerate convergence. Simulation tests on three distribution network examples of different scales show that the improved ADMM method proposed in this paper has better convergence and better optimal solution.