First, clean the yam, peel it, soak it in tap water for a period of time to prevent it from being oxidized and blackened in the air, heat the pot and pour in an appropriate amount of cooking oil. When the oil in the pot is hot, put the yam in the pot and fry for three minutes. Pick up the yam and drain the oil and put it on a plate for later use. Pour the oil out of the pot, clean the pot, add appropriate amount of water, add sugar after boiling, and boil. When the sugar and water are thick, add yam and medlar and stir well, then add a little salt to the pot and serve after refrigeration.