The present paper reports the study on visible/near-infrared (Vis/NIR) diffuse reflectance spectroscopy for nondestructive measurement of vitamin C in tangerine (Nanfeng, Jiangxi). In the wavelength range of 350-1800 nm, principal component analysis (PCA) and partial least squares (PLS) were used to build mathematic models with respect to pre-processing spectra. The principal components (PCs) and wavelength selection for calibration model were determined based on full cross validation and regression coefficients. The results, based on prediction for 10 unknown samples, are 0.813, 2.112 mg (100 g)(-1) and -0.810 mg (100 g)(-1) for prediction correlation coefficient, root mean square error of prediction, and prediction deviation, respectively. The analysis methods and conclusions of this experiment will provide some reference values for non-destructive measurement of vitamin C and other quality indices in Nanfeng tangerine using Vis/NIR diffuse reflectance spectrometric technique.