The invention discloses a brightener dropping device and an application method. The brightener dropping device comprises a cavity body which is used for holding a brightener, wherein the upper end of the cavity body is provided with a brightener adding hole and a ventilating hole, the lower end of the cavity body is provided with a brightener discharging hole and a pressure measuring hole, the brightener dropping device further comprises a dropping connector which is in communication with the brightener leasing hole through a first pipeline, the dropping connector is higher than the upper end of the cavity body, the first pipeline is provided with an electromagnetic pump, the brightener dropping device further comprises a positive pressure detecting meter which is in communication with the pressure measuring hole through a second pipeline, the second pipeline is an n-shaped airtight pipeline which is arranged at the side of the cavity body, and the top end of the second pipeline is higher than the upper end of the cavity body. According to the brightener dropping device, the device can drop the brightener into a dish-washing machine in an automatic and quantitative mode, and can automatically monitor the using allowance of the brightener and timely remind a user to add the brightener, thus the operation and using are convenient. The invention further provides the dish-washing machine using the brightener dropping device. Automatic dropping of the brightener can be achieved, and the operation and using are more convenient.