N-vinyl pyrrolidone grafted polylactic acid (M-PLA) scaffold for tissue engineering was fabricated by thermal induced phase separation technique. The effect of polymer concentration, water/ dioxane ratio and coarsening temperature on the scaffold porosity and structure were studied with grafting ratio of 36%. And the effect of grafting ratio on the scaffold structure was also studied with the same preparation condition. The hydrophilisity and protein adhesion of M-PLA scaffold was tested. The results showed that, the porosity of the M-PLA scaffold with grafting ratio of 36% decreased with the increase of polymer concentration, water was helpful to form a regular porous structure, the pore size and the porosity of the scaffold increased with the decrease of coarsening temperature. With increasing grafting ratio, there were no significant changes of the porosity and pore size of the scaffold, but better pore regularity and connectivity compared with PLA scaffold. The hydrophilisity and protein adhesion test showed that the M-PLA scaffold had higher hydration, protein adhesion ratio and better biocompatibility.