The work aims to study the rheological property of the edible inkjet ink and obtain the effect of binder chitosan oligosaccharide added on the rheological property of the ink. The rheological property of chitosan oligosaccharide-based edible inkjet ink was studied by means of shear rate scanning experiment and amplitude scanning experiment, and the effect of different amounts of chitosan oligosaccharide on the rheological property of ink was analyzed. When the mass fraction of chitosan oligosaccharide changed from 0 to 4.2%, the shear stress of the ink increased from 3.823 Pa to 4.837 Pa, shear viscosity increased from 4.47×10−3 Pa•s to 5.56×10−3 Pa•s, elasticity modulus decreased from 3.99×10−3 Pa to 3.33×10−3 Pa, viscous modulus increased from 0.0199 Pa to 0.0283 Pa, complex modulus changed from 0.0203 Pa to 0.0285 Pa and strain phase error changed from 78.75° to 83.59°. The addition of chitosan oligosaccharide has certain influence on the shear stress, shear viscosity, viscous modulus, elasticity modulus and strain phase error δ of the ink.