The invention discloses a circuit for testing admittance and a phase angle of a secondary circuit through a pilot frequency admittance method. The circuit comprises a secondary circuit, wherein one end of the secondary circuit is connected with a pilot frequency single source, the other end of the secondary circuit is connected with a current test circuit, and the two ends of the secondary circuit are further connected with a voltage test circuit. A signal reflecting the current which is measured by the current test circuit in the secondary circuit and a signal reflecting the needed secondary circuit end voltage measured by the voltage test circuit serve as the input signals of the admittance and phase angle test circuit, and the admittance and phase angle test circuit output the admittance amplitude and the phase position amplitude of the secondary circuit. The circuit for testing the admittance and the phase angle of the secondary circuit through the pilot frequency admittance method has the advantages of being clear in functions of all parts of the circuit, easy to implement, capable of testing the admittance and the phase angle of the secondary circuit, less in components, simple in circuit, good in stability, high in safety and the like.