The invention discloses a preparation method of frozen mango pulp. In the process that mangoes are made into the mango pulp, the mangoes are easy to deteriorate due to imperfect sterilization measures, and a conventional preparation method for the mango pulp has the defects that high temperature instantaneous sterilization at 130-135 DEG C is adopted, bacteria are sterilized, at the same time, the color of the pulp is changed, the original mouth feel is changed or disappears, and the loss of nutrient components is generated due to high temperature. The preparation method disclosed by the invention comprises the following steps of selecting mangoes, cutting off mango stems, sending the mangoes without the stems into a brush machine, and spraying water for cleaning the surfaces of the mangoes; disinfecting the cleaned mangoes with an 80-100PPm chlorine dioxide solution; unpeeling the disinfected mangoes and removing kernels of the unpeeled mangoes so as to obtain mango flesh; preparing the mango flesh into the pulp with a pulping machine, and filtering the pulp with a 60-80 mesh filter net; putting the filtered pulp in the same batch in a storage tank for uniform stirring; and precooling the pulp to 0 DEG C by a telescoping water freezing precooling machine, and then lowering the temperature of the precooled pulp to minus 18 DEG C within 6-8 hours. According to the prepared mango pulp, the total bacterial count is controlled to be 10000cuf/mg or below, and high-temperature sterilization is not needed, so that the original flavor, the original mouth feel, the original color, and the original nutrient components of the mangoes are reserved.