<p>Biomass-derived nitrogen self-doped carbon quantum dots (N-CQDs) were synthesized by the hydrothermal method using soybean residue as both nitrogen and carbon sources. The N-CQDs were applied to the study of cell multicolor imaging and temperature sensing in living cells. The experimental results show that N-CQDs have strong fluorescence intensity, good biocompatibility, good cell membrane penetration, good cell imaging performance and strong temperature sensitivity. In the temperature range 25 ~ 60℃, the intensity of the N-CQDs decreased with increase of temperature, and showed a good linear relationship. At 60℃, the relative fluorescence intensity was quenched by 65%. The results show that the soybean residue N-CQDs have high application potential and value in the field of fluorescence temperature sensing in living cells, and are of great significance for the development of nondestructive cell measurement nanothermometers. It is expected that the N-CQDs may establish as a temperature-sensitive fluorescence nanoprobe widely used in biomedical fields such as cell research.</p> Graphical abstract <p></p>