The invention relates to a tooth harmonic coil turn number determination method capable of realizing a compound excitation characteristic of a synchronous generator. The method comprises the following steps: determining the turn number of an exciting winding according to the design requirements of rated data, performance indexes and the like of the generator; selecting an appropriate tooth harmonic winding pitch according to a principle that the induced electromotive force of the single turn of tooth harmonic coil is maximal, and determining the number n of the tooth harmonic coils in each pole; according to a target of maintaining the terminal voltage constant, determining exciting currents of n different working conditions from no load to a rated load; calculating a single-turn induced electromotive force of each tooth harmonic coil under each pole in n different working conditions from no load to the rated load; establishing a solving model according to a tooth harmonic excitation system equivalent circuit and the exciting current required by maintaining the terminal voltage of the generator constant under n different working conditions from no load to the rated load, and calculating the turn number of each tooth harmonic coil. The tooth harmonic coil turn number determination method has the advantages of clear physical concept, simple calculation and the like and has very strong actual application value.