This paper take predictor-corrector interior point method and branch-bound method applied in reactive power optimization. Prediction-corrector interior point method for global optimization, and branch-bound method to deal with discrete variables (transformer tap and capacitor, reactor switching group number). To the reality, this paper take minimizing loss of network as objective, through the IEEE14-bus system calculations, it is showed that this algorithm effectively reduces the loss of network, and it has calculating fast and a good convergence characteristics.