The effects of fermentation temperature on the microorganisms and product quality of low-salt soy sauce were investigated. In particular, low-salt soy sauce was fermented at 45 ℃, 35 ℃, 25 ℃, and natural conditions for analyses of the microbial count, physicochemical indicators, and quality indicators of mature soy sauce mash during the fermentation process. Different temperatures had varying degrees of influence on the fermentation of low-salt soy sauce. Yeast cells underwent rapid death during high-temperature fermentation at 45 ℃, while the yeast count remained relatively high (6.00 lg CFU/g) throughout the entire fermentation process at other temperatures. This resulted in significant differences in total microbial counts among temperatures. High-temperature fermentation at 45 ℃ improved the fermentation rate; however, the contents of reducing sugars (2.52 g/100 g) and sweet amino acids (11.92 g•kg-1) were higher and the biogenic amine content (78.88 mg•kg-1) was lower than those for fermentation at other temperatures. Fermentation at 45 ℃ was not conducive to the formation and accumulation of volatile flavor compounds in low-salt soy sauce, particularly phenolic and ester compounds, while a lower fermentation temperature was more favorable for the accumulation of phenols and esters. A sensory evaluation indicated that soy sauce fermented at 35 ℃ had the best sensory quality, followed by soy sauce fermented at 45 ℃. Soy sauce fermented at 25 ℃ and under natural conditions had poorer color and aroma attributes. In addition, fermentation at medium-to-low temperatures (35 ℃, 25 ℃, and room temperature) led to significant film production on the surface of the soy sauce mash during the late stage of fermentation. In summary, fermentation at 45 ℃ ensured normal liquid-state fermentation of low-salt soy sauce; however, the flavor and color were less favorable. The results of this study can serve as reference for the optimization and control of the low-salt soy sauce fermentation process in the future.