An electroluminescence(EL) device with structure of ITO//ZnS/SiO2∶PVP//Al was fabricated by spin coating with the mixing solution of ZnS/SiO2 quantum dots(QDs) and PVP.The EL emission spectrum consists of green emission in 510-560 nm and weak violet emission around 400 nm.Through analyzing the EL spectrum we find that the above two emissions both come from the defect energy level of ZnS,where the green emission peak is due to the lower defect energy level,while the violet emission is from the higher defect energy level which can trap electrons more easily.During the process,the energy level step formed by PVP can enhance the probability of trapping electrons effectively for the higher defect energy level,the luminous efficiency of higher energy band is increased,and the color coordinate of devices varies from(0.37,0.42) to(0.30,0.34),approaching to white light emission.