A device and a method for detecting a distance from a balloon to an ingot tank is provided. The device comprises a set of photoelectric transmitting tube and photoelectric receiving tube which are arranged in a height range of a balloon, Wherein a light beam between the photoelectric transmitting tube and the photoelectric receiving tube is arranged to be tangent to an appropriate balloon, and is used for detecting whether the balloon is located at an appropriate position according to a number of pulses received by the photoelectric receiving tube in one period of rotation of the balloon.