This study tested the development of bechamel sauce with different ratios of soy milk to milk(0:4, 1:3, 1:1, 3:1, 4:0) to examine changes in quality characteristics. Proximate composition analysis showed a decrease in salinity with increasing amounts of soy milk, while the moisture content and, density increases. The highest pH values were found for a 1:1 ratio of soy milk to milk (S2) and the lowest pH values were found for a 0:4 ratio of soy milk to milk (CON). The L-value decreased, while a and b values increased with increasing amounts of soy milk. In the stability test, segregation occurred in CON after 5 days, while the highest segregation occurred at a 4:0 ratio of soy milk to milk (S4). The sensory evaluation results showed that the color, thickness, savory flavor, and savory taste increased with increasing amounts of soy milk. In the acceptance test, a 1:3 ratio of soy milk to milk (S1) and a 1:1 ratio of soy milk to milk (S2) had the highest acceptance scores (p<0.001) for appearance, taste, texture, and overall acceptance.