Abstract: On the basis of studying the relationship between the excitation adjustment coefficient and reactive power of generator, a new power flow calculation model by considering the adjustment coefficient of generator is presented in this paper. The assumption of PV node in traditional power flow calculation is abandoned in the model, and the nodal voltages for generators are seen as variables that vary with reactive power. The power system with IEEE14, 30 and 118 nodes and one province power grid are taken as test cases, the results show that the new model has better convergence for both small-scale power system and large scale power system than that of traditional calculation algorithm. In addition, the results of power flow calculation are more accurate, the distribution of the reactive power between generators is more reasonable, and it has advantage on maintaining the voltage stability and lowering system loss.