Sulfamethoxazole (SMS) was determined using a straightforward, quick, and sensitive spectrophotometric approach that was described, the method is centered on the development of a stable water-soluble a product that maximum absorption at 515 nm by Trifluoperazine hydrochloride's oxidative coupling reaction (TRF) and (SMS) utilizing nitrate cerium ammonium (CAN) acting as the oxidizing agent in a medium of acidic. Depending on the concentration of SMS, the law of beer was the concentration of range of 2-38g.ml^-1and a molar absorptivity of 1.47 x 10³ L.mol^-1.cm^-1, one that is related of -0.026 to +5.5, and in a concentration, Beer's law is applied. a relative standard deviation was 0.136 to 0.319%.the sensitivity of Sandell's was 0.172 g.cm^-1 and the limit of detection (LOD) were 0.645 g/ml^-1 and (LOQ) were 2.15 g/ml^-1 The suggested approach has been effectively used to determine SMS in several.