Blood stains serve as crucial evidence aiding investigators in solving cases, linking suspects to crimes, and reconstructing crime scenes. Criminals frequently attempt to remove blood stains from clothing through washing, potentially altering or eliminating stained areas, thereby complicating investigators' efforts to locate and extract these stains. To uncover the optimal method for detecting blood stains on laundry, enhance the accessibility of physical evidence, and provide robust evidence for criminal case detection and court sentencing, this study evaluates the effective ness of amino black 10B, acid yellow reagent, luminol, tetramethylbenzidine, and a 415 nm light source in revealing latent bloodstains on cotton, cotton-polyester blends, and polyester textiles in both dark and light hues, following washes with enzyme-containing and enzyme-free detergents. For occult blood traces on washed light-colored polyester-cotton blend and polyester textiles, the apparent effective ness ranked in descending order was: luminol, amino black 10B, acid yellow reagent, 415 nm band light source, and tetramethylbenzidine. For light-colored cotton textiles, the order was luminol, amino black 10B, 415 nm band light source, and acid yellow reagent. For dark-colored cotton, polyester-cotton blend, and polyester textiles, both luminol and acid yellow reagent exhibited good results, with luminol demonstrating superior performance. In conclusion, luminol reagent has proven to be exceptional in revealing occult blood traces on washed textiles, which is of paramount importance in solving crimes.