Abstract: Aiming at the defects of traditional high sugar jam, loquat and mulberry were used as main raw materials to develop low sugar compound jam. The ratio of loquat in the compound fruit pulp, citric acid addition, white granulated sugar addition and pectin addition were screened by a single factor experiment. According to sensory score, Box-Benhnken central composite design experiment was adopted to optimize the formula of low sugar loquat mulberry jam. The results showed that the optimal formula parameters were as follows: The ratio of loquat in the compound fruit pulp was 32%, the addition of citric acid was 0.1%, the addition of white granulated sugar was 20.5% and the addition of pectin was 1.0%. Under these conditions, the sensory score of low sugar loquat and mulberry compound jam was (91.29±1.02) scores. The product was bright purple in sauce color, harmonious sourness and sweetness, rich in fruit flavor, moderate in viscosity, good in gel stability, total acid content 1.01%, pH value 3.64, moisture content 67.84%, ash content 0.36%, protein content 0.82%, vitamin C content was 8.69 mg/100 g, soluble solids content 31.51%, compared with GB/T 22474-2008 "Jam" which required less than 65% sugar content, the total sugar content of the product was only 27.02%, which met the demand for low sugar in the jam market, and the microbial indexes were in line with the national standards. The results could provide theoretical reference for the product development and industrial production of low sugar loquat mulberry compound jam.