Edible starches from potato, cassava and corn were micronized to different granularity by the vacuum ball-milling machine. Particular tokens were made on the changes of starch's granularity, appearance, aggregation structure, etc. SEM analysis indicated that the appearance of starch granule changes evidently during the ball-milling treatment. The granule broke at the areas of stress concentration first, such as disfigurements, flaws and crystal areas. When the milling time increases, the homeostasis of micronization and conglobation existing together was appeared; furthermore, it can be seen that the decrease of the starch granules size is not only from the surface layer step by step, but lots of thicker layers desquamate around the granule, and many layers take breakdown from the core during the process of the micronized treatment.