Wrap the tinfoil around the purple potatoes, put them in the oven, set the upper and lower heat, pay attention to set the temperature of the oven to 200 degrees, and bake for about 60 minutes. In addition, the baking time of the purple potatoes according to the size of its head to set, if the size of the purple potatoes is small, the baking time is relatively reduced, and set to 50 minutes can be, at the end of the baking, you can use chopsticks to poke a hole in the body of the purple potatoes, if it can be easily inserted, then it means cooked.