A bubble detection system to detect bubbles in photoresist. The system includes photoresist at least one tank, a buffer tank, a pump, and a bubble sensor. The photoresist tank provides the photoresist. The buffer tank stores the photoresist from the photoresist tank. The pump pumps the photoresist from the buffer tank to an end terminal. The bubble sensor is set between the buffer tank and the pump to detect bubbles in the photoresist, and outputs an alarm signal when bubbles are detected. The nozzle is set at the end terminal to output the photoresist.