Stabilities of black-soybean pigment on pH,temperature,sunlight,oxidant,reductant,amino acid and metal-ion were studied.The results indicated that black-soybean pigment was stable at acidic and shelter circumstance,heat-resistant.K⁺、Mg²⁺ had not significant effect on stability of pigment,while Fe³⁺,Cu²⁺,Zn²⁺ had obviously effect on its stability.The pigment got poor stability to oxidant and re-ductant.