In view of the requirement of network partitioning for reactive power and voltage control on regional reactive power balance，a concept of regional reactive power margin is proposed.An optimal network partitioning model is developed for reactive power and voltage control considering electrical coupling degree between buses，static reactive power balance ability，and partition requirement of reactive power reserve.This model includes two objective functions，i.e.，minimizing the sum of squares of all areaselectrical radii and maximizing the regional reactive power margin in the area with minimum reactive power margin.The constraint on the model is static reactive power balance in all areas.For the characteristics of the model developed，the multi-objective adaptive evolutionary programming algorithm is used for solution.Finally，simulation results on an IEEE 39-bus system and comparisons with other network partitioning methods show that the method proposed is effective.