The NdFeB thin films are fabricated by a DC magnetron sputtering system. We find W underlayer is favorable to pseudomorphic growth of Nd 2Fe 14B crystallites with predominant c-axis perpendicular alignment. Through manipulating the sputtering parameters, this kind of pseudomorphic growth can be effective in a certain film thickness range. In our case, the crucial thickness value is estimated to be about 30 nm, which is thick enough for application of the ultra-high density perpendicular magnetic recording media. Beyond this range, misfit dislocation will be formed in the films, the films become more soft due to the formation of soft phases. We also discuss the magnetization reverse mechanism of the interested film with the thickness of 15 nm. Its magnetization reverse process is found to be mainly controlled by magnetization incoherent rotation.