Abstract: Using bleached shellac as raw material, water soluble shellac-based carbon quantum dots(shellac-CQDs) with blue fluorescence were synthesized by hydrothermal and one-step synthesis method. Their composition and structure were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM) and dynamic light scattering(DLS). The analysis results showed that shellac-CQDs mainly contained C and O elements, which were composed of aromatic ring structure and a large number of oxygen-containing functional groups, with an average particle size of 2.0 nm. The spectral tests showed that the maximum excitation wavelength and emission wavelength of shellac-CQDs were 320 and 432 nm, respectively. The maximum absorption wavelength in the UV-Vis spectrum was 289 nm. Based on the good fluorescence properties of shellac-CQDs and the quenching effect of tetracycline hydrochloride on its fluorescence, a new method for the detection of tetracycline hydrochloride using shellac-CQDs as fluorescence sensor was established. The results showed that there was a good linear relationship between the fluorescence peak areas and the concentration of tetracycline hydrochloride in the range of 0.02-0.10 g/L. The detection limit of this method was 0.01 g/L. It has been preliminarily applied to the detection of tetracycline hydrochloride in tap water or feed, and the recovery rate of the samples was 96.9%-107.7%, and the relative standard deviation(RSD) was between 1.9% and 5.5%, indicating that this method has high accuracy, good repeatability and potential practical application value.