The present invention discloses a conductive sensor and a urinal having conductive sensor. Said conductive sensor is installed in the sewer pipe of the urinal or toilet, which comprises an insulating body and a detecting electrode used for detecting the electric conductivity of the liquid in the sewer pipe. Said conductive sensor also comprises a self-cleaning device used for cleaning the end of the detecting electrode. Said self-cleaning device comprises a housing, a piston unit and a brush head unit. A water inlet pipe connected with the tap water pipe and a water outlet pipe connected with the sewer pipe are installed to said housing. Said brush head unit comprises a brush head used for cleaning the end of the detecting electrode. Thus, the detected result of conductive sensor and the urinal having conductive sensor are more reliable and the device is easy to be maintained.