The chemiluminescence intensity of luminol-dissolved oxygen was decreased when cephalosporins were mixed with luminol. The decrease chemiluminescence intensity was linear with the logarithm of cephalosporins concentration over the range from nanogram to microgramme level, with the limits of detection at nanogram level. The sensitivities of determination for cephalosporins were in the order of cefoperazone > ceftriaxone > cefuroxime > cefaclor > cefalexin > cefradine. The proposed method was applied to monitor the excretion of cefradine in human urine after taken cefradine capsules. The possible chemiluminescence mechanism and relationship between the determination sensitivities and generations of cephalosporins were also discussed.