High-quality Zn1-xMgxO thin film was grown on Si substrate by pulsed laser deposition (PLD). x-ray diffraction patterns indicated that the film was c-axis oriented, the full width at half maximum of (002) peak was only 0.211°, and no phase separation was observed. Transmission electron microscopy(TEM) verified the c-axis orientation of the Zn1-xMgxO thin film. Regular diffraction spots can be observed by TEM. Photoluminescence spectrum was measured at room temperature. The near-band-energy emission peak of the Zn1-xMgxO thin film has a blue shift of 0.4 eV from that of ZnO, and the ratio of near-band-energy to the defect-level peak intensity was as large as 159. These results indicate that Zn1-xMgxO thin film can have potential applications in optoelectronic devices.