Abstract: The effects of the concentration of magnetic nanoparticles, isothermal temperature and the rate of cooling/rewarming on the crystallization behavior of VS55 during the devitrification process under isothermal scanning and continuous scanning methods were studied using a cryomicroscope system. The results show that: With the increase of nanoparticle concentration and isothermal temperature, the growth rate, initial size and crystal density of ice crystals increase generally, promoting the growth of ice crystals. Continuous scanning of VS55 with different magnetic nanoparticle concentration groups was performed, and the results were consistent with the isothermal scanning conclusions. The crystal devitrification growth of the magnetic nanoparticle-added solution was obvious. When the cooling rate is increased to 5 ℃ / min, the initial size of ice crystals and their number increase significantly and the growth rate also increases slightly. A cooling rate above 5 ℃ / min has little effect on the growth of ice crystals. As the heating rate increases, the ice crystal size, growth rate, and number of ice crystals decrease.