Crystallization which plays an important role in the separation and purification of high purity compounds,is a traditional separation and purification technology widely used in chemical,pharmaceutical and other fields.The spectral process analysis technology based on the concept of quality by design provides an efficient and intelligent support for the monitoring,feedback and control of crystallization process.In this paper,applications of several process analysis technologies,such as attenuated total reflection Fourier transform infrared spectroscopy,Raman spectroscopy,near infrared spectroscopy and focused beam reflectance measurement are reviewed.The status,advantages and disadvantages of the above technologies are systematically summarized,and their future development trends are prospected,in order to provide an effective reference for the on line monitoring of crystallization process.