Abstract: Based on the chemiluminescence (CL) catalysis of vitamin B12 (VB12 in luminol-H$_{2}$O$_{2}$ system, a novel capillary electrophoresis-chemiluminescence (CE-CL) method was developed for the accurate determination of this important nutrient substance. First of all, sodium hydrosulfite (Na$_{2}$S$_{2}$O$_{4})$ was found to be used as an competent reduction reagent to pre-reduce VB12(Co(III)) into VB12(Co(II)), which produced strong CL emission in the CL reaction of luminol-H$_{2}$O$_{2}$. In this process, some interfering CL noise was observed and capillary electrophoresis (CE) was taken to remove it by efficient separation. In this way, VB12 could be reduced gently and determined accurately by the catalyzed CL signal with our lab-constructed CE-CL system. The proposed CE-CL determination could be finished in 20 min with a detection limit (LOD) of 2$\times $10$^{-7}$ mol/L ($S$/$N$=3), a linear range from 6$\times $10$^{-7}$ to 6$\times$10$^{-4}$ mol/L ($r^{2}$=0.968) and a relative standard deviation (RSD) of 2.4{\%} ($n$=9). Utilizing this method, satisfactory results were obtained by testing VB12 tablets with a recovery of 97{\%}$\sim $106{\%}. Compared to previously reported CL analysis of VB12, we dealt with the interference components in pre-reducing solution for the first time to gain more reliable data with convenient operations.