[en] In the present work, tungsten (W) coatings with thickness range of 35–130 nm on the diamond particles were prepared by magnetron sputtering method, and then the Diamond/Al composites were prepared by the vacuum infiltration method. The prepared W coatings were smooth and dense on all the facets of the diamond particles. Moreover, the presence of W-coatings inhibited the interfacial debonding phenomenon and improved the interfacial bonding between diamond particles and Al matrix. The Diamond/Al composite with the 45 nm W-coating achieved the maximum thermal conductivity (622 W/(m·K)). To the best of our knowledge, it is the highest thermal conductivity obtained in the Al matrix composites reinforced with 100 μm diamond particles with coatings. Based on the Hasselman and Johnson (H-J) model, the thermal conductivity behavior of the Diamond/Al composites has been discussed. It indicates that the magnetron sputtering is a feasible and successful method to prepare thin and reliable tungsten coatings for the Diamond/Al composites. - Highlights: • W-coatings on diamond particles were prepared by the magnetron sputtering method. • W-coatings were smooth and dense on all the facets of the diamond particles. • The interfacial bonding has been significantly improved by W-coatings. • The highest TC for Al matrix composites reinforced with 100 μm diamond was obtained. • Magnetron sputtering is a successful method to prepare thin and reliable coatings.