The invention relates to a distribution network load prediction method and a distribution network load prediction system based on transformer operation data. According to the method and the system, transformers under feeders in a distribution network are used as calculation units to get the corresponding optimal fitting curve of each transformer; and under the corresponding optimal fitting curve of each transformer, the sum of load predicted values of all the transformers on the same feeder is calculated to get the feeder load predicted value of the feeder, and the regional load predicted value of a to-be-predicted region is obtained. As the load change trend of each transformer is analyzed separately, space division of the to-be-predicted region is more refined, and the accuracy of load prediction is increased. As the load natures of the power supply regions of the transformers are often similar and the influencing factors are the same, the method and the system can effectively avoid complex load classification and influencing factor analysis so as to simplify the calculation process and improve the speed of load prediction.