The invention discloses a reactive power compensation device which belongs to the technical field of reactive power control of electric power systems. According to the reactive power compensation device disclosed by the invention, a parallel capacitor is adopted as a basic reactive power compensation means, and is set as grade-III compensation; for realizing the fast response of reactive power control, a SVC (static Var compensator) is adopted as a rapid control compensation means, and is set as grade-II compensation; for realizing the continuity of reactive power control, a SVG (static Var generator) is adopted as a continuous control compensation means, and is set as grade-I compensation; in the processes of reactive power compensation and voltage control, a graded response mechanism is adopted to carry out three-grade model coordination control, namely, firstly, the grade-I compensation is acted so as to realize rapid continuous reactive power compensation, then, the grade-II compensation is acted so as to realize rapid discrete reactive power compensation, and finally, the grade-III compensation is acted so as to realize large-capacity reactive power compensation. According to the reactive power compensation device, the problem of reactive compensation after large-scale intermittent energies are combined to a grid can be solved, and the precise adjustment on reactive power compensation and voltage control can be realized, so that the requirements of voltage operating of electric power systems can be met.