In order to explore chemical composition and the causes of candied sweet potato white spot under different conditions, the composition were analyzed by scanning electron microscopy, fourier transform infrared spectroscopy and ion chromatography, and the case of produced white spot of candied sweet potato in different storage were also studied. The results showed that the reducing sugar and total sugar contents of candied sweet potato white spot were 636.76 mg/g and 961.34 mg/g, respectively. Mainly the sugar composed of galactose, glucose, fructose and galacturonic acid. After storage 150 d at 25 ℃, it was found that nitrogen packing most conducive of generating white spot from candied sweet potato, followed by vacuum packaging, common packaging produced minimal, the white spot producing rate of three kinds packaging were 80.12%, 64.38% and 26.88%, respectively. With the storage temperature increased, the white spot producing rates gradually increased and they were found to be 10.00%, 19.38% and 26.88%, respectively, at 4 ℃, room temperature and 25 ℃ of common packaging sample.