Abstract: In order to explore the preparation technology of controlled non-crystallization of starch, cassava starch was selected as the raw material, and the impacts of alkali concentration, treatment temperature, reaction time, material-liquid ratio on the crystallinity and crystal structure of cassava starch were systematically studied. It was found that the influence of treatment time and material-liquid ratio on the crystallinity during the non-crystallization of starch was non-linear, which the linear correlation coefficient r between the material-liquid ratio and crystallinity was 0.14, and the r of treatment time and crystallinity was-0.02. And the variation of its crystal form was difficult to control. The impact of alkaline concentration and treatment temperature on the crystallinity in the process of starch non-crystallization was negative linear correlation, which the r of alkali concentration and crystallinity was -0.97, and the r of process temperature and crystallinity was -0.84, and can effectively control the change of crystal form of cassava starch. With the increase of alkali concentration from the 0.25 mol/L to the 1.25 mol/L, the crystal form of starch was changed from type A to amorphous state, and the relative crystallinity gradually decreased from 23.63% to 0. Therefore, the controlled non-crystallization of cassava starch can be prepared via a high temperature alcohol-alkali process.