The quality of hay can directly affect the price of hay and also livestock productivity.Many kinds of methods have been developed for detecting the quality of hay and the method of near infrared spectroscopy (NIRS) has been widely used with consideration of its fast,effective and nondestructive characteristics during detecting process.In the present paper,the feasibility and effectiveness of application of NIRS to detecting hay quality were expounded.Meanwhile,the advance in the study of using NIRS to detect chemical compositions,extent of incursion by epiphyte,amount of toxicant excreted by endogenetic epiphyte and some minim components that can not be detected by using chemical methods were also introduced detailedly.Based on the review of the progresses in using NIRS to detect the quality of hay,it can be concluded that using NIRS to detect hay quality can avoid the disadvantages of time wasting,complication and high cost when using traditional chemical method.And for better utilization of NIRS in practice,some more studies still need to be implemented to further perfect and improve the utilization of NIRS for detecting forage quality,and more accurate modes and systematic analysis software need to be established in times to come.