Radical polymerizations of styrene in the presence of C-60 have been conducted at 90 degrees C in benzene using benzoyl peroxide (BPO) as initiator. The behaviors of C-60 are investigated by monitoring BPO concentration, C-60 content, and polymerization time. It is found that C-60 acts like a radical absorber which multiply absorbs primary radicals from BPO and propagating radicals. Therefore, in the presence of C the yield and molecular weight decrease significantly. However, the molecular weight distribution is narrowed down by its coupling characteristics. At the beginning of the reaction, owing to the radical-absorbing effect of C-60, it makes the chain-propagation restricted. However, the number of polystyrene chains added to C-60 increases with polymerization time. Direct dilatometric experiment proves that C-60 is mainly as inhibitor for radical polymerization of styrene by benzoyl peroxide. Besides, the glass transition temperature (T-g) of the copolymers increases with increasing content of C-60.