Alkali-earth metal doped C60 thin film is produced by evaporating C60 powder together with Sn powder. We analyze the influence of doping on component, structure and conductivity of C60 thin film by measuring the SEM, UV optical absorption and resistivity change with temperature of the film. The results show that after doping the tiny drops forming the film stick out of the surface, and the size of the drops increases slightly. So the electron emission threshold value of the film will lower. The Sn atom doped form the impurity level in the forbidden band. So the electron absorption transition changed from directly to indirectly, and the electrical conductivity changed too from insulator to n-type semiconductor.