Abstract：This paper studied the stability of purple corncob pigment that was impacted by the light，oxidizing a— gent，reducing agent and food additive，in the acidic conditions．The results show that sunlight speeds up purple corncob pigment degradation．S~ong oxidant hydrogen peroxide on purple corncob role of pigment bleaching is the most obvious，followed by ascorbic acid，sodium benzoate and sodium sulphite anhydrous reductant． Sucrose has little efect on the stability of purple corncob pigm ent and higher concentrations of sucrose also has the hyperchromic effect．Purple corncob pigment has a better value of the development and utilization in the food industry．