A detecting circuit for detecting a battery having a first and second electrode, includes a contacting portion electrically connecting to the first electrode of the battery, a seesaw electrically connected to the second electrode of the battery, and an actuator electrically connecting to the second electrode of the battery. One end of the seesaw electrically contacts with the contacting portion when the battery have a protection circuit. The actuator is configured for providing power onto another end of the seesaw to separate the contacting portion with the seesaw when the battery has no a protection circuit. The detecting circuit can truly and handily judges whether the detected battery has the protection circuit according to the action of the seesaw.