ZnO thin films, used as polymer protection layers against ultraviolet radiation and atomic oxygen for space application, were deposited on polyimide foil substrates using a cathodic vacuum arc deposition technique. A fragmentation test was employed to investigate the influence of deposition pressure on the adhesion of ZnO thin films. It was found that all the samples have good adhesive properties. Low deposition pressure is beneficial to the adhesion of ZnO films and polyimide substrates. Scanning electron microscopy was also employed to investigate the surface morphology of ZnO films that had suffered from large strain. No large areas of film detachment were found.