This paper presents a method of multi-objective reactive power optimization of hybrid AC/DC power system considering load uncertainty to study the influence of load uncertainty to reactive power optimization. The objectives are minimization of active power loss and maximization of voltage stability margin, load inaccuracy based on the normal random distribution is considered in the modal. The reactive optimization is nonlinear, multivariate and multi-constraint, a hybrid algorithm of interior point method and genetic algorithm is adopted to solve the upper optimization modal, and an improved genetic algorithm is adopted to solve the lower optimization modal. The proposed method is tested in a modified hybrid AC/DC power system based on the IEEE 30-bus system. The results demonstrate that the proposed method is feasible and effective.