Ad-blue liquid level sensor assembly is able to detect the concentration, temperature, solubility and level of urea solution in real time(continuously), and remind the vehicle owner of any abnormality through signal output. The structure of the product matches the shape of the urea tank and integrates a water valve, which can control the urea thawing function under low temperature conditions and also could thaw the urea in a short time to make the SCR system work normally.