The invention relates to the field of
seawater index detection devices, and provides a liquid concentration detection device. The liquid concentration detection device comprises a concentration detection mechanism and a cleaning mechanism, the concentration detection mechanism comprises a measuring cylinder and a
laser displacement sensor, a gravitometer is arranged in the measuring cylinder, andthe measuring cylinder is provided with a gravitometer locating piece for locating the gravitometer; the
laser displacement sensor is arranged over the measuring cylinder, a
laser emitting direction of the laser displacement sensor is same as a length direction of the gravitometer, and the laser emitting direction faces towards a top end of the gravitometer; the cleaning mechanism comprises a drain
pipe communicated with the bottom of the measuring cylinder and a flush
pipe for flushing towards the top end of the measuring cylinder, a drain valve is arranged on the drain
pipe, a flushing end of the flush pipe faces towards an opening part of the top end of the measuring cylinder, and the flush pipe is provided with a water pump. The liquid concentration detected by the liquid concentrationdetection device is highly accurate. The invention also provides a
seawater concentration detection set, the
seawater concentration detection set comprises the liquid concentration detection device,and thus,
salt pond concentration detected by the seawater concentration detection set is also highly accurate.