The invention discloses an energy-saving control cabinet and a calculating method of the reactive compensation electricity saving amount of the energy-saving control cabinet. The energy-saving control cabinet comprises an energy-saving power distribution controller, an air switch, a molded case circuit breaker, a load control switching switch and at least one capacitor bank; the energy-saving power distribution controller is a hub unit of the energy-saving control cabinet, collects external voltage signals and external current signals, and collects switching value signals of the air switch; the energy-saving power distribution controller outputs control switch signals to the load control switching switch, checks working condition data of a distribution room and inputs command information; the energy-saving power distribution controller calculates the corresponding reactive compensation electricity saving amount through the collected voltage signals and the volume put into the capacitor bank. By means of the energy-saving control cabinet and the calculating method, on the basis of distribution room working condition parameters collected by the energy-saving control cabinet, calculation of reactive loss electric quantity reduced by reactive compensation power factor promoting of the energy-saving control cabinet is achieved, and the technological support and the theory support are provided for the development of energy-saving and consumption-reducing work of power enterprises.