Abstract: The aim of this study was to establish the mathematical model based on visible / near infrared diffuse reflectance spectroscopy for detecting the color of Manai grape,and to evaluate its application value. With the brightness L*and chromaticity coordinates a*,b*as evaluation indexes,different stoichiometry modeling methods,different spectral preprocessing methods and different effective wavelength intervals were discussed,and the unknown samples were predicted with the optimal model in order to validate the accuracy. The results showed that in the whole spectral range,L*got the best result with partial least squares( PLS) combined with the second order derivative,scattering spectra pretreatment methods,the SECV,R2 CVwere 0.4591,0.9476; optimal methods for a*,b*were the first derivative combined with the weighted multiple discrete correction processing,the SECV were respectively 0.1239,0.4496,and the R2 CVwere 0.9508,0.8648.Application of quick and nondestructive detection based on visible / near infrared reflectance technique was feasible in measuring surface color of Manai grape,models of L*and a*were moderate,the accuracy of b*model remained to be further improved.