The reaction of carbonyl compounds with ammonium/amino acids in the atmosphere can generate brown carbon (BrC), which have significantly impact atmospheric radiation and global climate. This study investigated the ability to generate brown carbon through the reactions of carbonyl compounds (glyoxal, glyoxalic acid, and pyruvate) with ammonium (ammonium sulfate) and glycine, as well as alanine. Ultraviolet–visible absorption spectroscopy analysis of the reaction solutions revealed that the combination of glyoxal and glycine synergistically enhances BrC formation. When ammonium sulfate was added, the mixed reaction of glyoxal with glycine and ammonium sulfate exhibits absorbance characteristics that are second only to the complex system of glyoxal and glycine. The value of light absorption intensity in the reaction system of mixing glyoxal, alanine, and ammonium sulfate is slightly higher than that of the system with alanine alone. These results suggest that the ammonium sulfate plays both a synergistic and competitive role in the reaction between carbonyl compounds and amino acids, particularly in the wavelength range of 300–400 nm. Under acidic conditions, the reaction rate of the glyoxal-glycine-ammonium sulfate mixture is accelerated. These findings are crucial for understanding BrC formation pathways in the atmosphere and predicting the contribution of carbonyl compounds to BrC formation in chemical models.