An optimal power flow（OPF） model based on rectangular power-current hybrid mismatch formulation is developed. In the proposed model， buses with power injections are formulated as power mismatch power flow constraints， while buses without power injections are formulated as current mismatch power flow constraints. The hybrid model combines the advantages of both power mismatch and current mismatch formulations. For buses without power injections， the hybrid model shares the advantages of current mismatch formulation: the first derivatives become constants， and the second derivatives are zeros， which make Jacobian and Hessian matrices easier to compute. The hybrid formulation is also easier to handle buses with power injections than current mismatch formulation and suitable for the nonlinear predictor-corrector interior point OPF. Numerical studies on several systems up to 2 746 buses indicate that the proposed approach shows better convergence performance and computational efficiency， especially for large-scale power system OPF problems with a large percentage of zero-injection buses.