The invention discloses a nitride red luminous material with long afterglow and a preparation method thereof. The material has a chemical formula of M<2-x-y>Si5N8:xEu,yRe, wherein in the formula, M is one or more elements selected from Sr, Ca, and Ba, x is more than or equal to 0.005 and less than or equal to 0.15, y is more than or equal to 0.005 and less than or equal to 0.15, and Re represents at least one element selected from the following elements: Tm, Dy, Pr, Nd, Sm, Gd, and Lu. The material comprises at least two rare earth elements. The preparation method obtains a red luminous material with long afterglow, which has the advantages of good chroma, high brightness, and long afterglow time, has the advantages of simple technology, available raw materials, and low cost, and obtains a nitride red luminous material with long afterglow.