The relationship between the spectrum characteristics and nitrogen content of soils in citrus orchard of the Three Gorges Reservoir Area was studied by analyzing the visible-near infrared spectrum. The results showed that the soil reflectivity increased lineally as the wavelength increases across the visible spectrum and reached a stable plateau in the short wavelength near-infrared region（780-1 750 nm）without much fluctuation. In the long wavelength near-infrared region （1 750-2 400 nm）the reflectivity of the soils was higher with higher fluctuation. There were three strong absorbance peaks around 1 416, 1 913 and 2 209 nm, respectively, in the long wavelength infrared region. Soil available nitrogen content and total nitrogen content were positively correlated with soil light reflectivity but negatively correlated with catoptric-spectrum values reciprocal logarithm. At 541 nm of visible light region, a high positive correlation was found between the available nitrogen content and the first derivative of the soil reflective spectrum with a correlation coefficient of +0.605** and the best fitting equation was y=2E+09x2-3E+06x+890.49, where R2=0.5， and x is the first derivative of the soil reflective spectrum. At 1 909 nm of the near-infrared long wavelength region, the correlation between the total nitrogen content and the reciprocal-log values of the reflective spectrum of the soils was the best with a correlation coefficient of -0.612**, and the best fitting equation was y=1.372 1x2-2.107 5x+0.859 2, where R2=0.4, and x is the reciprocal values of the log reflective spectrum of the soils.