A reactive power support pricing method based on branch's dissipation power components is presented. Firstly， the equipments with reactive power regulating capability are treated as reactive power sources， and the loads（both real and reactive） and generators（real power） which rely on the reactive power sources are treated as the consumers. Each of reactive power sources for reactive power support is modeled as a shunt susceptance called“cost susceptance”， and each of reactive consumers is modeled as an equivalent nodal injection current source based on the steady power flow or state estimation results. Finally， both reactive power fractions and corresponding reactive power support cost induced by reactive power consumers on cost susceptance are determined based on the algorithm of dissipation power components. The corresponding reactive power costs induced by a consumer'active power（reactive power） on all cost susceptance are summed up， and the unit reactive power support cost is calculated to get the reactive power support price of reactive consumers. Comparing with the existing methods， the proposed method has the following properties: it covers the total system cost of reactive power supporting; it is applicable for any transmission systems of looped configurations; it does not need any assumption or simplification; and it considers the interaction between active and reactive powers. Simulation results show that the proposed method is effective.