Abstract: Monascus pigments(MPs), the secondary metabolites produced by Monascus purpureus, are usually fermented with rice.Monascus pigments not only have anti-inflammatory, anti-cancer, anti-obesity, hypoglycemicand other effects, but also can be used for food coloring in different colors.In recent years, MPs have become one of the fastest developing food additives among microbial natural pigments.The rice bran was investigated as a substrate for utilization in submerged fermentation, which was used to reduce the cost of MPs production, improve the ability of Monascus purpureus to produce Monascus pigments, and increase the added value of rice bran.Three nutrients, mannitol, ZnSO₄ and NH₄NO₃, were selected by the single factor test, and their additive amounts were optimized by response surface optimization.Characteristics of MPs were analyzed by High Performance Liquid Chromatography(HPLC)and Thin-Layer Chromatography(TLC), and their safety was verified by the detection of citrinin.The single factor test showed the following results: xylose, xylitol, fructose and mannitol in carbon source could promote the production of MPs, the color value of mannitol was the highest, reaching 1 138.90 U/g at 505 nm; NaNO₃ and NH₄NO₃ in nitrogen source could promote the production of MPs, the color value of NH₄NO₃ was 252.64 U/g at 505 nm; ZnSO₄ in inorganic salt was beneficial to the production of pigments, and the color value was 396.00 U/g at 505 nm.The response surface center was determined as mannitol(5.10%), ZnSO₄(0.40%), and NH₄NO₃(1.00%)by the steepest climbing test.The response surface results showed that the maximum yields of MPs were obtained by rice bran(5.00%), added with mannitol(5.10%), ZnSO₄(0.40%), and NH₄NO₃(1.00%).The color value of MPs after optimization was 1 250.83 U/g, which was 11.78 times the equivalents of pure rice bran fermentation.At the same time, the optimized color value was 71.41% of rice color value.Six major components of MPs were significantly improved by response surface optimization, including two red pigments(rubropunctamine and monascorubramine), two orange pigments(rubropunctatin and monascorubrin), and two yellow pigments(monascin and ankaflavin).Then, the two red pigments showed the most significant improvement.The optimized citrinin and MPs yield were lower than that of rice medium, which was safer than rice medium.This study provided useful data for MPs production with the agricultural by-product.