Objective By studying the hydrophobic property, the work aimed to prove the structure and property differences between different hydrogenated DLC films prepared by the source electrode and the immersion PECVD method, and demonstrate that hydrogenated DLC film prepared by immersion PECVD method is more suitable for the applications requiring highly hydrophobic surface modification. Methods PECVD chamber was filled with methane and hydrogen gas mixture, some quartz substrates were mounted on the powered electrode to grow conventional hydrogenated DLC films; other quartz substrates were mounted on an insulating sample holder that was facing the powered electrode to grow polymeric DLC films. PECVD chamber was filled with acetylene, hydrogen, and tetrafluoromethane gas mixture, quartz substrates were mounted on an insulating sample holder that was facing the powered electrode to grow fluorine-doped hydrogenated DLC films. UV-visible absorption spectra of DLC films were measured using a UV-visible spectrophotometer, SEM and AFM devices were used to analyze the surface morphology of the obtained DLC films. Contact angles with water, glycerin, and glycol were measured and used to calculate the surface free energy of the polymeric and conventional hydrogenated DLC films. The contact angles and the surface free energies of the two types of hydrogenated DLC films were compared, and the possible cause was discussed according to the microstructure of the polymeric DLC films. The contact angles of fluorine-doped and nondoped hydrogenated DLC films were compared and the result was discussed. Results The polymeric DLC films had quite different contact angles and surface free energies comparing to conventional hydrogenated DLC films with an identical optical gap. The polymeric DLC film had bigger contact angle, smaller surface free energy, and therefore better hydrophobic properties. The maximum contact angles with water for the polymeric and conventional hydrogenated DLC films were 91.2° and 79.2° respectively. Polymeric DLC film had a higher hydrogenation rate for its sp3 carbon atoms, and this could be the cause for its low surface free energy and good hydrophobic properties. The fluorine-doped DLC film had a lower contact angle than both the polymeric and conventional hydrogenated DLC films with an identical optical gap, this contradicted the reported phenomena of increased contact angles for fluorine-doped DLC films. Conclusion Polymeric DLC film has better hydrophobic properties. Considering its other characteristics such as lower internal stress, wider range of optical gaps, and higher deposition speed, polymeric DLC film is more applicable in the field of medical and optical protection films. The fluorine-doped DLC film grown with the immersive PECVD method has lower instead of higher hydrophobic properties, and further investigations are needed to elucidate its cause.