A chemiluminescence (CL) system for menadione sodium bisulfite (MSB) combined with a flow-injection system is presented in this paper. It is based on CL produced by the oxidation of bisulfite liberated from MSB by Ce(IV). The system responds linearly to MSB concentration in the range of 0.01 ∼ 10 μg/mL with the detection limit (3τf) of 2 x 10−3μg/mL. The relative standard deviation for 2 μg/mL MSB was 3.45% (n=10). The system has been applied successfully to the determination of MSB in injections.