In order to find out the rule for temperature of mechanical heart valves to influence diamond like carbon (DLC) film, the DLC films were deposited on mechanical heart valves by the pulsed laser deposition while the temperature of the mechanical heart valve were kept chamber temperature and 150°C respectively and other experimental conditions unchangeable. The microstructure of the film was detected by the visible Raman spectroscopy. The topography and roughness of the film were detected by the atomic force microscopy (AFM). The experimental results demonstrate that when the temperature of the mechanical heart valve increases from chamber temperature to 150°C, change of the film microstructure would not be obvious. The roughness of film surface would reduce. The diamond like carbon film would exhibit strong adhesion to mechanical heart valve.