Lithium acrylate (LiAA) was applied as a functional monomer to modify the surface properties of polypropylene films via photografting polymerization in a precipitation reaction system. Two-step photografting polymerization technique was adopted with benzophenone (BP) as the photoinitiator and methanol as the solvent. ATR-FITR spectra proved the occurrence of grafting polymerization of LiAA on the substrate. Gravimetric analysis was performed to investigate the influences of some important factors on the photografting polymerization of LiAA. SEM was utilized to investigate the topography of the grafted film. The experimental results indicated that elongation of the irradiation time could increase the grafting yield (Yg) and Yg performed a maximum at a certain concentration of LiAA. SEM images showed that regular particles evenly dispersed on the surface of the grafted film.