Disclosed are a flushing control system and a flushing control method of a toilet bowl. The flushing control system is used for controlling flushing time of a drainage device and comprises a master control circuit, a sensor device, a first switch, a second switch and a third switch. The master control circuit is connected with the sensor device and the drainage device; the first switch is connected with the master control circuit to send a seating signal, the second switch is connected with the master control circuit to send a flushing signal, and the third switch is connected with the master control circuit to send a seat opening signal. The master control circuit controls the drainage device to delay to flush according to the signal send from the first switch, or to flush instantly according to the flushing signal send from the second switch, or to start the sensor device according to the seat opening signal send from the third switch. According to the flushing control system and the flushing control method, different practical applications are taken into consideration comprehensively, power consumption is lowered, service life is prolonged and accuracy is high.