Abstract: The optimum processing technology and suitable formula of low sugar jam using Sargassum siliquastrum were studied. Fuzzy comprehensive evaluation was used to judge the quality of jam. Single-factor was employed to determine the right conditions among the ratio of liquid to solid, the time of concentration and quality improvers. The process parameters were optimized by neural network and the neural network model was established. The results showed that when the ratio of liquor to material was 5, the concentration time was 25min under 80℃, the ratio of sugar to material was (1. 69±0. 01) ∶ 1, the citric acid addition was 0.65%～0.70%, and CaCl2 addition was 0.02%, the total sugar was 29.73%. The Sargassum jam with unique flavor had nice structure, taste, scents and spreadability and low sugar.