La0.67Ca0.33MnO3 grain films have been grown by pulsed electron beam deposition technology,and their magnetic and electronic transport properties investigated in detail.The influence of grain boundaries on the physical properties of La0.67Ca0.33MnO3 grain films were studied.Grain boundaries weaken the coupling between grains,resulting in a cluster spin glass state.The metal-insulator transition temperature (Tp) was shifted far below the ferromagnetic-paramagnetic transition temperature (Tc).At low temperatures,the electron transportation indicates a weak localization behavior,and under low magnetic fields,the intrinsic magnetoresisance effect is screened by the influence of grain boundaries.