The transparent conducting films have been investigated extensively because of their excellent electrical and optical properties in many applications. For producing the LCD (Liquid Crystal Displays) and OLED (Organic Light-Emitting Diode), the transparent conductive films are mainly deposited on the glass. Using the plastic substrate has the advantages of low cost, light-weighted, and flexible characteristics; it is considered as the candidate substrate material for the portable and flexible LCD. The surface roughness measured by AFM was in the range 2.63~11.1nm. The result shows that the crystallite size increases with increasing the r.f. power. The microstructure of ZnO film has a proud (002) orientation. The average transmittance of ZnO film can be obtained over 80% in the visible spectrum. The lowest resistivity obtained is 4.0×10-3 ohm-cm. The adhesion between ZnO films and PET substrate is good because there is no separate observed in this study.