This contribution reports a simple approach for preparing PMA/TiO2 composite. In this method, nano TiO2 powders are previously treated by a combined modification process, namely, the alkali-treatment followed by oleic acid surface-grafting, Before polymerization, the modified TiO2 nanoparticles are dispersed into the maleic anhydride (MA) solution to form stable homogeneous gel. When the reaction temperature is raised to 150 degrees C, the modified nano TiO2 can initiate the hi situ anionic polymerization of MA. Finally, the PMA/TiO2 composites are obtained, in which all the TiO2 are fully coated by MA polymer (PMA). Therefore, it is not needed to reclaim the nano initiators because they are blended into the prepared polymers as the nano fillers. TEM and SEM experiment results can strongly demonstrate that the TiO2 nanoparticles are homogeneously dispersed in PMA matrix. This approach is easy-to-operate and applicable to the preparation of other nano composites. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3582-3588, 2009