It is of practical significance to investigate the stability of vitamin C in complex vitamins （CVC） under different conditions， which will be helpful to improve the stability of vitamin C （VC） in the food system containing complex vitamins. In the present study， the content of vitamin C was determined by fluorescence analysis， and then the stability of CVC and VC was compared in different conditions including temperature， pH value， metal ions， light， redox reagents and carbohydrates， etc. The results showed that CVC displayed stronger heat resistance， alkali resistance and light stability than VC. The residue rate of CVC and VC decreased significantly as the hydrogen peroxide level increased， and was close to 0% after incubation with volume fraction 2.7% hydrogen peroxide. Moreover， epigallocatechin gallate didn't show concentration-dependence on improving the stability of CVC and VC， but lessened more CVC content than VC. Additionally， the effect of metal ions on CVC and VC stability was diverse， the residue rate of CVC was minimally affected by Mg2+ and Zn2+， but maximally by Fe3+ and Na+. However， the residue rate of VC was minimally affected by Na+， but maximally by Zn2+. Low concentration of glucose （≤5%） could only improve CVC stability， and high concentration of glucose （≥10%） could improve both CVC and VC stability. Together， these results indicated that CVC and VC exhibited different stability. Therefore， it should be adjusted processing conditions according to addition of the type of vitamin C in the food industry.