Starch solid system was used to investigate the effects of lipoxygenase, linoleic acid and water activity on the oxidation of ${eta}-carotene$ or ${alpha}-tocopherol$. ${eta}-carotene$ or ${alpha}-tocopherol$ was co-oxidized severely with linoleic acid by lipoxygenase, and these were reduced to 19% and 5% of initial concentration, respectively, after 2 days storage at $a_w$ 0.72 in the system. The concentration of ${eta}-carotene$ and the destruction rates were linearly correlated. However, the ${eta}-carotene$ was very stable in the system without linoleic acid and lipoxygenase. The oxidation products of ${alpha}-tocopherol$ were considered as ${alpha}-tocopheryl$ quinone and ${alpha}-tocopheryl$ dimer, and the level of ${alpha}-tocopherol$ quinone increased as the reaction time increased.