Volume holographic grating of Dichromated Gelatin(DCG) made of different kinds of gelatin may have different characteristics in diffraction efficiency,bandwidth and noise,which determines the application areas of the volume holographic grating.The diffraction characteristics of the volume holographic gratings made of three kinds of gelatin are studied through experiments.The experimental result shows that: 1) With the same fabrication parameters,volume holographic gratings made of GC-1 gelatin and GC-3 gelatin exhibit high diffraction efficiency (nearly 100%); 2) The bandwidth of GC-1 gelatin grating is 46 nm,while the bandwidth of GC-3 gelatin grating is only 17 nm; and 3) The GC-2 gelatin grating has low diffraction efficiency and bad curve.The study can provide a reference for selecting gelatin in fabrication of holographic grating for different application areas.