In order to enhance the surface wear properties of cast iron, some QT500 specimens are processed with JMG-GY-300D pulsed laser in different medium(air and water), and the microstructure, micro-hardness and frictional characterization are examined and analyzed. The experimental results showed that, after laser shock processing, a lot of dislocations and twins are found in the strengthening layer, hardness is improved significantly. The friction and wear behaviors are tested using a M200 friction and wear test apparatus under dry sliding condition. It is found that the main wear mechanism is adhesion wear, the friction and wear resistance of cast iron in water is better than in air.