The invention provides a leakage detecting protection circuit capable of periodically automatically detecting function integrity. The leakage detecting protection circuit comprises a main loop switch, a resetting button, a tripping coil, a silicon controlled rectifier, an induction coil for detecting leakage current, a self-induction coil for detecting a low-resistance failure and a control chip which drives the switching-on/off of the silicon controlled rectifier by a leakage current detection result, and further comprises a) a timer for periodically outputting a function integrity detection signal, b) a detection signal latching circuit, c) an analogue test switch for generating analogue leakage current, d) a delay output circuit and e) a sampling circuit, wherein the timer outputs the detection signal to the latching circuit and the delay output circuit; and if a function is detected to fail, the delay output circuit outputs a tripping signal to switch the silicon controlled rectifier on, and the main loop switch is switched off. The leakage detecting protection circuit has the main advantages of periodically automatically detecting whether the leakage protection function of the circuit is integral or not without annual testing and avoiding tripping within the service life of the circuit, along with more convenience of use.