Multi-port inverted matrix method is a universal parallel method for solving linear equations, which modifies only several parts from serial method, and is especial fit for rebuilding parallel program from serial one. The method has been used for some power system parallel analysis method, such aselectromechanical transient stability analysis and small signal stability, and the parallel efficiency is high. Based on the Multi-port inversed matrix method, a parallel Newton power flow algorithm is presented in this paper. Simulation results on a large inter-connected system with several network division modes show that the proposed algorithm is correct and more efficient on parallel process.