The invention provides an electricity stealing behavior identification method and device based on non-invasion load monitoring. By monitoring the current and voltage of electrical appliances, the kindand operation condition of a single load under the condition that the electrical appliances are simultaneously started in an internal load cluster can be obtained through analysis, wherein the operation condition comprises specific electricity consumption and starting and closing time records of the electrical appliances in different time starting periods. According to the method, by using parameter curves and power steady-state change, power transient-state change and power steady-state fluctuation characteristics of the electrical appliances, starting and closing time of the electrical appliances is decomposed from the total current and total voltage, electrical energy metering is conducted, and an obtained result is compared with an electric meter result for judging whether or not electricity stealing occurs. Through the above design, an effective and convenient mode is provided, the electricity stealing behavior is monitored and identified, an effective energy-saving measure is taken, so that the effective electricity utilization rate is maximized, the unnecessary loss and the illegal electricity stealing behavior are reduced, and collected electricity utilization data can provide data support for monitoring and development of future power.