Abstract: In the medium of HCl—KCl (pH 1～2) by means of cyclic voltammetry and differential pulse polarography (DPP),the mechanism of the electrode reaction for latamoxef sodium (Shiomarin) at static mercury drop electrode (SMDE) and hanging mercury drop electrode (HMDE) has been proposed. A sensitive method for the determination of nanomolar concentration of latamoxef sodium by DPP was developed. The peak potential was -0 62 V (vs Ag/AgCl). The linear range was from 1×10^-8 to 8×10^-4 mol·L^-1 , the detection limit was ca. 4×10^-9 mol·L^-1 (t_ac =90 s). The method was applied to the determination of latamoxef sodium in injection with satisfactory results. The possibility for the direct determination of latamoxef sodium in mimic urine sample was also studied.