With the increasing number of industrial-sensitive users and high requirements of power quality, the voltage sag problem has become an important part of power system studies. Application of STATCOM in the traditional method based on the inhibition of voltage sag, this paper proposes a new perspective. First of all, the point of view based on the improved fault point method, combined with compensation principle of STATCOM, each bus on the grid voltage sag frequency was evaluated. Furthermore, analysis of the impact STATCOM other buses on the inhibition of the grid voltage sag, proposed STATCOM distributed configuration. Finally, based on the bus voltage sensitive loads economic assessment, presented the concept of optimal allocation of STATCOM distribution network. By standard IEEE-30 bus system, it verify the theoretical analysis presented in this paper.