The present invention provides a liquid storage device relates to the field of semiconductor manufacturing technology comprising: a liquid storage tank, a liquid intake tube, a liquid discharge tube and a gas discharge tube; the liquid intake tube, the liquid discharge tube and the gas discharge tube are all connected with the liquid storage tank; the liquid storage device also comprises a gas compensating tube connected with the liquid storage tank; the gas compensating tube comprises a differential pressure mechanism and a gas storage tank; one end of the differential pressure mechanism is connected with the liquid storage tank, and the other end is connected with the gas storage tank; the differential pressure mechanism is used for controlling the connection or disconnection between the liquid storage tank and the gas storage tank according to the pressure difference therebetween.