Determination of vitamin C content of the main iodometry, spectrophotometry, polarimetry, HPLC, TLC scanning method and other methods of measurement, iodometric method for the measurement process is more cumber-some and difficult to exclude excipients vitamin C compound interference; higher spectrophotometry, HPLC, TLC scan-ning method of measuring instruments, and increased testing costs. In this paper, methods of physics, by means of linear regression theory, the use of vitamin C in different pH solution in the optical rotation were significantly different, and the differential characteristics of the optical rotation and a linear relationship between concentration within a certain range, by difference show the polarimetry VC injection of content were measured at the same time to study and analyze the influencing factors of the experiment. The results show that the VC injection in 2.50 mg/ml. To 12.5 mg/ml concentra-tion and differential optical rotation of the linear relationship, the related equation y = 0.1835 x + 0.0113, the correlation coefficient r = 0.996. Compared with other measurement methods, the method is simple and reliable, the result is rea-sonable, so as to achieve fast, simple and accurate determination of the purpose of the VC content, especially for small and medium-sized hospital departments for the rapid detection of drugs.