Objective To investigate the influence of humidity and load on the tribological properties of W doped diamond-like carbon(W-DLC) film on nitrided high speed steel. Methods W-DLC film was deposited on the nitriding high speed steel by unbalanced magnetron sputtering. Hardness and adhesion were measured through nanoindentor and scratch test. Friction coefficient and wear rate under varied humidity (30% and 60%) and load (10 N, 20 N, 30 N and 40 N) were investigated by friction and wear test. Scanning electron microscope with energy dispersive spectrometer was used to observe the morphology and analyze the chemical composition after wear, and Raman spectroscopy was applied for the analysis of the structure of the debris. Results The hardness and adhesion of W-DLC film were both improved after the nitridation of HSS substrate. Under the humidity of 30% and 60%, the friction coefficient of the film tended to increase and then decrease with the increase of load, of which the maximum value was achieved under the load of 30 N. The wear rate was both in proportion to the load when the humidity was 30% and 60%. In addition, the wear rate under the humidity of 60% was greater than that of 30%. The Raman spectra of debris indicated graphitization of W-DLC after grinding, while load and humidity little effect on the structure of the debris. Conclusion Plasma nitriding of high speed steel substrate could significantly improve the hardness and adhesion of W doped diamond-like carbon films.