Objective:To establish a method for the determination of erythromycin in erythromycin enteric capsules. Methods:UV spectrophotometry was performed. Sodium hydroxide reacted with erythromycin to obtain a unsaturated ketone having maximum absor-bance at 235 nm. The content of erythromycin in erythromycin enteric capsules was determined by the UV absorbance of the unsaturat-ed ketone. Results: The linear range of erythromycin was 51. 18-307. 08 μg · ml-1 ( r =0. 999 9 ) and the average recovery was 99. 9%(RSD=1. 2%,n=6). Conclusion:The method is simple,accurate,sensitive and reproducible, which can be used for the de-termination of erythromycin in erythromycin enteric capsules.