The invention provides a quick-freeze purple sweet potato zongzi and a preparation method thereof. The quick-freeze purple sweet potato zongzi is prepared by the following preparation method: (1) cutting a purple sweet potato into pieces, steaming until the sweet potato pieces are cooked, placing at the room temperature and drying for 4-12 hours; (2) preparing the purple sweet potato pieces into mashed purple sweet potato, placing the mashed purple sweet potato into the center of a glutinous rice ball, and then wrapping the glutinous rice ball by zongzi leaves to obtain the zongzi; (3) placing the zongzi into the water with a pH value of 5-7, heating up to 80-90 DEG C, then putting the zongzi into a pot, boiling, taking the zongzi out, cooling, washing with water with the pH value of 5-7,airing, and then performing quick-freeze treatment to obtain the quick-freeze purple sweet potato zongzi. The purple sweet potato is added in the quick-freeze purple sweet potato zongzi provided by the invention, so that the taste of the zongzi is improved, and thus a new taste quick-freeze purple sweet potato zongzi is provided. The quick-freeze purple sweet potato zongzi provided by the invention has great taste, tastes sweet but not greasy and also has a certain health care function, thus being suitable for all ages to eat.