Abstract: This study aimed to investigate the effects of Lactiplantibacillus plantarum HYY-S10 as a starter culture on the physicochemical properties, sensory quality, and volatile flavor compounds of fermented sausages. Sausages inoculated with HYY-S10 served as the treatment groups, while naturally fermented sausages and those inoculated with Lactiplantibacillus plantarum DMDL 9010 were used as controls. By varying the inoculation level of HYY-S10 (0.0, 0.2, 0.4, and 0.6 g/kg), a comprehensive evaluation was conducted, including physicochemical analysis, sensory profiling, and volatile flavor compounds characterization. The results indicated that the addition of HYY-S10 significantly (P<0.05) accelerated the fermentation process, as evidenced by a rapid pH drop and reduced thiobarbituric acid reactive substances (TBARS) values, demonstrating its potent acidification and antioxidant capacity. Concurrently, significant improvements (P<0.05) in color and texture parameters were observed. The volatile compound profile was notably enriched, with increased diversity and concentration of key volatile flavor compounds. Scanning electron microscopy further revealed that HYY-S10 effectively disrupted the integrity of muscle fibers. An inoculation level of 0.4 g/kg of HYY-S10 was identified as optimal, yielding sausages with the highest overall quality. These sausages exhibited the lowest pH, the highest lightness (L^*), the lowest yellowness (b^*), the maximum viable cell count (8.53±0.04 log CFU/g), and the highest overall sensory score. In conclusion, Lactiplantibacillus plantarum HYY-S10 is a promising starter culture that can comprehensively enhance the fermentation efficiency, physicochemical attributes, sensory acceptability, and microbial safety of fermented sausages.