The invention provides a near-
infrared spectrograph, which belongs to the technical field of photoelectric test. The invention is characterized in that a
near infrared light source and a collimating lens are matched up to constitute an illuminant
system. The back position of the collimating lens is suitably provided with a
light intensity modulation disc and an
optical filter, and then is suitably provided with a dual-light path changer consisting of a dual-light path episcotister and a reflector. The dual-light path changer is connected with an
integrating sphere light path arranged on the front part. A rotary sample
cell and a
photodetector connected with a
signal processor are suitably arranged on an
integrating sphere. The invention has simple structure, and the cost is low. Like a continuous
wavelength type
spectrograph when used, the invention makes use of a scaling method based on
continuous spectrum to analyze a special ingredient, and the characteristic
wavelength of the instrument does not need determining at the phase of research and development of the instrument. The invention makes use of the characteristics of large
band width of the
optical filter-type one, and the structures of the
integrating sphere, the dual light paths, the rotary sample
cell and so on to achieve the technical effects of a quasicontinuous
wavelength type
spectrograph, thus significantly improving the
signal to
noise ratio, the stability and the versatility.