Abstract: The fat content of traditional sausage was usually high, which did not meet the demand of low-fat healthy consumption and development. It was of great significance to study fat substitutes and make new low-fat sausage products. This study used pig leg meat as raw material and replaced 10%, 30% and 50% of fat in the original sausage ratios with pitaya fruit to analyze its effects on sausage protein solubility, colour difference, sensory quality, sulfhydryl content, surface hydrophobicity, fluorescence intensity, acid value and thiobarbituric acid reactive substances values (TBARs). The results showed that the total protein, myoplasmic protein and myofibrillar protein solubility were increased significantly with the increasing pitaya proportion (P<0.05) compared with the control group, and the 30% group increased by 12.1%, 8.4% and 18.6% respectively. The results of the sensory evaluation showed that 30% group was higher than other groups in all aspects. Compared to the control group, the 10% group showed a significant increase in sulfhydryl content and a significant decrease in surface hydrophobicity (P<0.05). In conclusion, the addition of red heart pitaya as a substitute for part of the fat in the sausage increased protein solubility, improved sensory quality and inhibited lipid oxidation, and the best quality of the sausage was achieved when the addition amount was 30%.