A self-cleaning toilet has: a toilet, a cleaning device, a solenoid valve and a blocking member. The toilet has a sitting toilet seat and a water tank. The sitting toilet seat is formed with a urinal, and one end of the urinal has an enlarged opening to form a seat, and the urinal tapers from the seat to the other end to form a drain elbow. The water tank is connected to the toilet with an outlet pipe, and the water tank is connected with an input pipe, a cleaning device is set in the toilet with a controller, and the controller is connected with a plurality of the ultrasonic transducers and a full water level sensor, The ultrasonic transducers are fixed on the inner wall of the urinal. The solenoid valve is connected to the input pipe, and a blocking member is connected to the drain elbow.