A CMOS driving circuit for active matrix type polymer electroluminescent displays was designed to develop an on-chip microdisplay on the single crystal silicon wafer substrate. The driving circuit is a conventional structure that is composed of the row, column and pixel driving parts. 256 gray scales were implemented using pulse amplitude modulation method. The 2-transistor driving scheme was adopted for the pixel driving part. The layout was carried out considering the compatibility with the standard CMOS process. Judging from the layout of the driving circuit, it turns that it is possible to implement a high-resolution display about 400 ppi resolution. Through the HSPICE simulation, it was verified that this circuit is capable of driving a VGA signal mode display and implementing 256 gray levels.