The invention provides a peach fermented product and a preparation method thereof. The method comprises the following steps: (1) removing the peach pits, crushing to obtain peach liquid, adding pectinase and cellulase into the peach liquid and performing enzymolysis, thereby obtaining enzymolysis liquid; (2) adding a carbon source, a nitrogen source and inorganic salt into the enzymolysis liquid, inoculating leuconostoc mesenteroides, and performing primary fermentation so as to obtain first fermentation liquor when the pH value of the fermentation liquor is reduced by over 0.5; (3) adding the carbon source and the nitrogen source into the first fermentation liquor, and inoculating compound lactobacillus and performing secondary fermentation, thereby obtaining second fermentation liquor when the total sugar content of the fermentation liquor is lower than 3wt%, wherein the compound lactobacillus comprises streptococcus thermophilus, lactobacillus delbrueckii subsp. bulgaricus and lactobacillus plantarum; and (4) uniformly mixing the second fermentation liquor, centrifuging, homogenizing and sterilizing the centrifuged supernatant, thereby obtaining the peach fermented product. According to the scheme in the invention, the peach fermented product with the advantages of low sugar content, good taste and unique flavor can be obtained in short fermentation time.