The invention provides a multi-rotor unmanned aerial vehicle system efficiency assessment method for power inspection. The method comprises the following contents: system efficiency is evaluated through indexes of multiple dimensions, and a value of the system efficiency is a product of the indexes of the multiple dimensions; the index of each dimension contains one or more levels of sub-indexes; a value of the last level of the sub-index is determined based on an actual condition of the index; and the index of each dimension or a value of each level of the sub-index except the last level of the sub-index is obtained through a calculation formula. According to the method, various indexes are classified comprehensively and objectively, weights are reasonably set, specific evaluation methods for all the levels of the indexes are explained respectively, the multi-rotor unmanned aerial vehicle system efficiency is quantitatively calculated, and the type selection and purchase of a multi-rotor unmanned aerial vehicle system for the power inspection are effectively guided.