The invention provides a user electricity utilization heating load adjustable capability assessment method based on numerical weather prediction. The method is characterized in that firstly, three quantitative indexes representing load adjustable capability are defined, including applicable regulating power Pcontrol, duration time tcontrol maintaining given regulating power, and electric quantity Wcontrol regulated in a power regulating period. Through a user electricity utilization heating thermal dynamic model, and introducing a temperature parameter of numerical weather prediction of a certain period, user electricity utilization heating load adjustable capability of the period in an interval satisfying comfortableness of human bodies is assessed. The method provides important reference basis for realizing that electric heating users take part in power grid load regulation. The method is advantaged by being scientific and reasonable, and having good applicability and good effects.