To establish the UV spectrophotometric method for the intermediate assay of piracetam injection, thus provides to the rapid determination method for its intermediate assay and enhances the production efficiency. Make the wavelength scanning of the standard solution for piracetam with UV spectrophotometer, and determine its best absorption wavelength. And then establish the absorbance to concentration curve of piracetam standard solution under the best absorption wavelength. According to the standard curve, we can determine the assay of piracetam in the product. The best absorption wavelength of piracetam is about 220 nm, and its linear regression equation of absorbance to concentration is Y = 0.1056X + 0.2202, R2 = 0.9999. The UV spectrophotometric method is simple, rapid and accurate to determine the intermediate assay of piracetam injection.