Abstract: A novel multi-objective reactive power optimization method of distribution network was proposed, which used complex affine power flow algorithm to compute the uncertainty resulted from DGs. It first established the interval multi-objective optimization model of network loss and voltage deviation. Then it described the DGs’ output and state variables as complex affine and computed the interval power flow by Ybus-Gauss iteration. In the process of optimum seeking with NSGA-II algorithm, it divided the individuals into several groups according to dominance relationship and calculated the interval crowded distance in the non-dominated layer to eliminate the faultage of Pareto-optimal front. The validation of the proposed methodology was demonstrated by using an IEEE33 system with DGs. The results shows that the proposed method can optimize the network loss and voltage simultaneously as considering the uncertainty of DGs.