The invention provides braise sauce. The braise sauce consists of, by weight, 20-30 parts of xylose-L-cysteine Maillard reaction intermediate, 5-7 parts of xylose, 0.05-0.12 part of sodium tripolyphosphate, 0.01-0.015 part of ethyl maltol (scorched-scent), 0.01-0.03 part of monascus red pigment, 0.02-0.05 part of caramel pigment, 0.02-0.04 part of xanthan gum and 0.01-0.015 part of potassium sorbate. The invention further provides a preparation method of the braise sauce. A product obtained at an initial stage of Maillard reaction is adopted, the Maillard reaction intermediate and amino acid and other amine compounds contained in meat perform follow-up Maillard reaction to enable braised meat in the sauce to be brighter in color and luster and fuller in fragrance. Due to the fact that the xylose is used as a main body of the braise sauce, the demands of persons who love to eat braised meat in the sauce and worry about getting fat can be met to the most extent.