A harmonic-characteristics based current pattern matching method for the non-intrusive power load monitoring and disaggregation is provided in this present invention, on the basis of establishing the load signature database, which comprises electrical appliance registration and load state word space initialization, data acquisition and data preprocessing, feasible state word space search based on table looking-up, the optimal matching of current pattern, and display and output of the monitoring and disaggregation results. The method improves the accuracy of disaggregation, and can achieves exact identification of operating states of appliances, and also can reduce the cost.