The invention provides a reduction method of a small hydropower station output scene. The reduction method comprises the steps of acquiring small hydropower station output scenes in one-to-one correspondence to small hydropower station output curves; respectively dividing the small hydropower station output scenes into a plurality of small hydropower output scene sets according to the characteristic that the small hydropower station output curves change with time; reducing the number of the small hydropower station output scenes in each small hydropower station output scene set to a corresponding target number; and synchronously adjusting the probability of the small hydropower station output scenes in each small hydropower station output scene set. During the small hydropower station output scene reduction process, the small hydropower station output scenes are placed in the plurality of scene sets for processing, the intrinsic distinctive characteristic among the small hydropower station output scenes is considered during the small hydropower station output scene reduction process, so that the small hydropower station output scenes in each small hydropower station output scene set have similar characteristic; and the small hydropower station output scene set acquired by the reduction method is used for fitting small hydropower station output characteristic, and the fitting accuracy is improved.