Syndiotactic polystyrene(sPS)/montmorillonite nanocomposites were prepared via in site intercalative coordination with Cp*Ti(O-C6H4-F)3/MAO/TiBA catalytic system The montmorillonite modified with 12-aminododecanoic acid can increase catalytic activity on some degree．The nanostructure features were revealded by X-ray diffraction and transmission electmn miemgraphs．It was found that montmoritlonite could be dispersed in the sPS as sheets of 40 nm thich by in-situ syndiotactic polymerization．However．the interaction between the organic material and silicate layer of clay is not thermally stable enoust

to resist the high melt processing temporature of sPS．so nanocomposite could not be achieved by melt mixing directly．The thermal properties of pure sPS and sPS/MTN were investigated．The crystallization temperature and relative crystallinity of the fabricated nanocomposite (3.57％ MTN wt in sPS) increased obviously

it also had good thermal stability

the thermal decomposition temperature was about 50℃ higher than that of the pure syndiotactic polystyrene．