To enhance photostability of Monascus pigment, glycinin was modified via glutamyl endopeptidase (GE), which had strict substrate specificity. The surface hydrophobicity of the 11S globulin after hydrolysis was analyzed, and protein/pigment complex was produced after enzymatic modification of the 11S. The binding properties (binding constant and binding capacity) and the light stability of protein/pigment complex were investigated. The results showed that GE had a significant effect on 11S surface character and Monascus pigment photostability. Surface hydrophobicity of 11S increases with the degree of hydrolysis (DH) increased after GE modifying as the inner hydrophobic groups exposed. At pH 7.0, the binding constants of Monascus pigment and 3% (m/V) 11 S reached the maximum of 215.00 U/g pro when the DH was 1.50%. After 24 h light exposure, the protein/pigment complex had the color value retention rate of 90% which highly improved the light stability of Monascus pigment