Multi-spectral color synthesis image was extracted directly from R, G, B band of the multi-spectral image. However, due to different performances of the spectral response of multi-spectral imaging detector resulting in the color cast of the synthetic color image, in order to reproduce true color, the color correction was needed. For the lack of traditional white balance method and colorimetric synthesis method, an improved white balance method based on the spectral information was presented for color correction to multi-spectral color synthesis image. It is proved that this method is simple, does not require the standard true color image in the correction process, and does not need to predict the spectral reflectance of all features, but also improves the traditional algorithm, making the images more realistic.