The invention discloses a customer electricity utilization differentiation characteristic-based combined short-term load forecasting method. The method comprises the following steps of: analyzing differentiation characteristics of electricity utilization customers, establishing a costumer portrait technology-based comprehensive electricity utilization customer evaluation system, and putting forward a fuzzy clustering-based electricity utilization customer classification method; and putting forward a combined short-term load forecasting method on the basis of an analytic hierarchy process by combining the characteristic that degrees of influence, suffered by different types of customer electricity utilization, of different factors such as policies, economics and environment. Instances provethat the forecasting method disclosed by the invention is reliable in precision; and meanwhile, technical data basis is provided for the transformation and upgrading of power supply services by different classifications and electric load forecasting values of customers.