A high yield of environmentally friendly N,S-codoped (N,S-CDs) and N-doping carbon points (N-CDs) carbon dots was achieved through a biochemical oxidation reaction at room temperature in this study. Acetaldehyde, sodium hydroxide, benzotriazole (BTA), and 2-mercaptobenzimidazole (MB) with a similar structure were used as raw materials. The microstructure and properties of the corrosion inhibitor for Q235 steel were evaluated by various experiments. The results demonstrated enhanced corrosion inhibition rates of the N,S-CDs compared to the N-CDs using electrochemical tests (93.83% vs 77.65%) and weight loss experiments (96.35% vs 91.65%) at 50 mg/L, respectively, compared to the blank material, indicating that N,S codoping can significantly improve the corrosion inhibition effect of carbon dots. The significant improvements were attributed to the formation of dense adsorption films and the hydrophobic properties of N and S-CDs nanoparticles on the steel surface, leading to an effective barrier against corrosion. The findings from this study provide important experimental data for potential industrial applications and hold important practical value in the field of pickling corrosion inhibitors.