A system for monitoring electronic circuit configured to monitor circuit parameters of an electronic circuit is provided. The system for monitoring electronic circuit includes an observing point monitoring circuit, a system control circuit, and a signal measuring circuit. The observing point monitoring circuit includes a plurality of sensor circuits arranged in an array. The sensor circuits respectively sense the circuit parameters of a plurality of observing points in the electronic circuit. The system control circuit selects at least one of the sensor circuits to sense the circuit parameters. One of the selected sensor circuits outputs a sensing signal. The signal measuring circuit receives the sensing signal and analyzes an electrical characteristic of the sensing signal to obtain a monitoring result of the circuit parameters. A method for monitoring electronic circuit is also provided.