Abstract: An indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect peanut in food, based on Ara h 6, a main allergen in peanut.The polyclonal antibody was prepared by immunizing New Zealand rabbits with Ara h 6.Those parameters were optimized as following.The concentrations of the coating antigen, polyclonal antibody against Ara h 6 and horseradish peroxidase conjugated goat anti-rabbit IgG were 1μg/mL, 1:50000 and 1:5000 respectively.The inhibition equation of indirect competitive ELISA was obtained as I= 21.418lgC-6.0633 (I stand for inhibition ratio and C stand for mass concentration) and the curve was linear in range of 16.5～10000ng/mL.Thus, this method has good sensitivity and wide range for the detection of Ara h 6 in peanut food.