The invention discloses a load characteristic classification and synthesis method based on frequency domain indexes. Firstly, electrical transformer districts to be classified are obtained form a monitoring control and data acquisition system, data are preprocessed, normalization processing is conducted the data, the data are represented through per unit values, an average is obtained according to the data in one or more weeks, and a typical daily load curve is obtained; then, based on a defined frequency domain index description system, an appointed clustering method is adopted for obtaining electrical transformer district types similar to frequency domain characteristic parameters, and finally typical load curves of classified users and frequency domain index description sets of the typical load curves are obtained. Compared with traditional load classification and synthesis methods, the load characteristic classification and synthesis method has the advantages that the number of data dimensions can be reduced effectively, computation overheads and memory capacity are reduced, and the load classification effect is similar to that of the traditional methods.