The utility model discloses a resolving circuit of a rotary transformer. The resolving circuit comprises a resolving chip, a power amplifier, an interference inhibition unit, a rotary transformer and a control chip. The resolving chip is provided with an excitation signal output terminal and a digital quantity output terminal. The excitation signal output terminal is connected with a signal input terminal of the interference inhibition unit. The digital quantity output terminal is connected with the control chip. A signal output terminal of the interference inhibition unit is connected with a signal input terminal of the power amplifier. A signal output terminal of the power amplifier is connected with the rotary transformer. A sinusoidal signal output terminal and a cosine signal output terminal of the rotary transformer are connected with the resolving chip through a matching impedor. The resolving circuit of the rotary transformer has the beneficial effect that, the interference inhibition unit is added between the power amplifier and the resolving chip, a structure of the resolving circuit is optimized, and development demands of high speed and miniaturization of the resolving circuit of the rotary transformer are satisfied, hence numerical magnitudes for representing an electrical position of a motor are obtained, and a servo motor is controlled.