A system is provided for detecting a liquid sample, and includes: a flow cell assembly formed with a sample receiving space therein, and inlet and outlet channels extending to the sample receiving space for guiding the liquid sample into and away from the sample receiving space; a sensor device including a sample detecting unit that is disposed in the sample receiving space, and that is operable to detect the liquid sample and to generate a detection signal accordingly, and a signal conducting unit that is connected electrically to the sensor device for conducting the detection signal therefrom; and a liquid introducing unit and a liquid discharging unit coupled to the inlet and outlet channels and cooperating therewith to form an introducing path and a discharging path for introducing the liquid sample into and for discharging the liquid sample from the sample receiving space, respectively.