A method and system for detecting an appliance based on users' feedback information, particularly a nonintrusive load monitoring method and system based on a user's feedback information and a joint strategic decision search algorithm are disclosed. By means of obtaining the users' feedback information on an appliance inputted by users or a search result of the appliances being confirmed by the users to generate a mapping between the model of the appliances and at least one load signature of each model of appliances; the users' feedback information is recorded into a smart meter or a cloud computing system, and a mathematical analysis is further used to compute an occurrence of any one signature of the appliance and the identification rate of each signature; then the joint strategic decision search algorithm automatically identifies various models of appliances and analyzes the operating states of the electric appliances in homes or offices.