The effects of pH, different concentrations of sugar, temperature, light, ultraviolet, nuclear radiation, phosphorous buffer, vitamin C, H 2O 2, and sodium benzoate on the red pigment of Cadiaeum virigatum var. pictum form platyphyllum were studied. It was indicated that this red pigment was a good pigment which was anti reductive, acid and basic tolerant, sugar tolerant, heat tolerant and light tolerant.