The invention relates to a glass hydrometer detecting / calibrating device. The glass hydrometer detecting / calibrating device comprises a holder, a thermostatic bath, a glass measuring cylinder, a real-time calibration liquid level monitoring device, a liquid level adjusting device, a glass hydrometer positioning device, a scale line recognizing device, a weighing device and a computer. The novel glass hydrometer detecting / calibrating device is developed based on the fundamental principle, namely a static liquid weighing method and for solving the major problems of an existing device. The whole device is composed of the thermostatic device, the scale line recognizing device, the glass hydrometer positioning device, the real-time calibration liquid level monitoring device, the liquid level adjusting device and the computer system, and therefore, the calibration of any scale point of a glass hydrometer in the whole measuring range of (500-3000) kg / m3 can be realized by use of only one environment-friendly calibration liquid; the calibration process can be finished by use of manual operations or automatically.