Disclosed are an intelligent safety relay and a circuit applied thereby. The intelligent safety relay includes: a first processing chip MCU A, a second processing chip MCU B, first and second input driving circuits, first to third input sampling circuits, first and second diagnostic signal generation circuits, first and second logic circuits, a diagnostic signal detection circuit, first and second relay driving circuits, and first and second relay circuits. The first processing chip MCU A and the second processing chip MCU B can automatically control, based on samples of the input driving circuits taken by the input sampling circuits, connection or disconnection of contacts in the first and second relay circuits so as to switch on or off an output.