The two are not the same, different sources and different uses. Tapioca is a starch extracted from the tuberous roots of the tropical plant cassava, tapioca can not be eaten raw, because it contains hydrocyanic acid, a natural toxin, which meets a high temperature of more than seventy degrees will disappear, and therefore the consumption of tapioca must be cooked before eating, potato starch is extracted from the starch of potatoes, there is no natural toxins, even if eaten raw, will not be poisonous situation occurs. Tapioca in the heat will become transparent, there is a certain toughness, can be used for a variety of food processing, and potato starch in life will be treated as a condiment, fried vegetables or soup, starch will play a role in the role of juice, in the frying of some foods, you can also wrap potato starch in the outer layer of the ingredients, it will make the fried food more crunchy.