Abstract: In this paper, taro starch as raw material treated by pullulanase debranching in different time, retrogradation at 4℃ was used to prepare starch nanoparticles. The structure and morphology of taro starch and starch nanoparticles were characterized by Zeta potentiometer, Fourier transform infrared spectroscopy, differential scanning calorimeter, X ray diffractometer and scanning electron microscope. The results showed that the average size of taro starch nanoparticles obtained by different enzymolysis time of (4, 6, 8 and 10 h)were 354.7, 235.4, 274.6 and 400.9 nm, respectively. Fourier infrared spectroscopy showed that there were no new characteristic peaks in taro starch nanoparticles, but the intermolecular force and hydrogen bonding were enhanced. Compared with the taro starch, the gelatinization temperature and enthalpy of the starch nanoparticles decreased, and the range of gelatinization temperature increased. The X-ray pattern changed from A-type to V-type, and the relative crystallinity decreased obviously. The taro starch nanoparticles were polygonal or spherical, the specific surface area increased, and there was a certain phenomenon of reunion.