The invention discloses a peak clipping and valley filling-oriented electricity utilization behavior analysis method. The method comprises the following steps: clustering main network load data in a historical period by utilizing an expectation maximization algorithm, so as to obtain grouping results, at different dates in the historical period, of the load; carrying out parallel hard clustering algorithm on user point-by-point load data at the date contained by each group, so as to obtain the grouping results, at different date groups, of the user; and comparing the load characteristics of the main network date group with the load characteristics of the grouping result, under the date group, of the user, so as to obtain a peak clipping/valley filling mode matching results, at different dates in history, of the user and target objects of off-peak electricity utilization. According to the method disclosed in the invention, the user electricity utilization behaviors under massive data can be analyzed to improve the user behavior positioning correctness, so that decision reference is provided for effectively developing the client services, improving the customer satisfaction degree and reducing the operation risks. The invention furthermore discloses a peak clipping and valley filling-oriented electricity utilization behavior analysis system.