A review.With the development of new technologies, a new technol. of mass spectrometry has been developed in the process of drug anal., which can not only carry out static quality control of drugs, but also dynamic anal. of pharmaceutical processes, in vivo and metabolic processes.The commonly used technol. in mass spectrometry is gas chromatog. combined with mass spectrometry.By means of complementary advantages, the quant. test speed, test accuracy, test sensitivity and identification ability are improved to meet the requirements of high precision and high throughput in today's drug anal.The article starts with a theor. overview of gas chromatog. and mass spectrometry, and then expounds the application of mass spectrometry in drug anal.