Long-wavelength fluorescence of carbon dots (CDs) show the great importance in multiple fields, especially for the biochemical sensing. Here we proposed one type of CDs doped with nitrogen and sulfur through the hydrothermal method, which exhibited the obvious yel-low-fluorescence in aqueous. Importantly, their fluorescence intensity of CDs decreased with pH decreasing in the acidic range, thus a linear relationship between pH and fluorescence intensity was established, and exhibiting the potential of pH sensing. Additionally, in-troducing tigecycline into CDs resulted in their decreased fluorescence, thus we further established a strategy of detecting tigecycline with the concentration range of 200 μM to 7 nM. Meanwhile, we elucidated the static quenching as the major mechanism for CDs responding tigecycline, which was induced by the formed new complex between CDs and tigecycline. Furthermore, the practicality of the method was verified by examining the recovery of tigecycline in the actual lake-water samples.