Microstructure, hardness and toughness as well as the thermal stability of W/B4C multilayer coating synthesized by ion beam sputtering were investigated. The results show well-defined layered structure and uniform monolayers can be found in the as-deposited multilayer coatings with various period thickness at fixed period ratio (W:B4C= 1: 1.5). The crystallinity of W layer and the roughness of W/B4C interfaces are changed as the period thickness increasing. It can be concluded that the nano multilayer coatings have superior strengthening and toughening effects. The hardness of as-deposited (W-5.2nm/B4C7.6nm)(20), (W-10.(5nm)/B4C15.8nm)(10) and (W-14.5nm/ B4C21.5nm) 7 coatings is greatly enhanced and higher than that of pure B4C coating, and the toughness of W/B4C multilayer coating is significantly higher than that of pure B4C coating. Subsequently, the investigations about thermal stability of (W-10.5nm/B4C15.8nm)(10) multilayer coatings indicate that the layered structural is stable when the heat treatment temperature is lower than 500 degrees C. With increasing of heat treatment temperature, the oxidation of W layer and the formation of WO3 compounds were found. The nano layered structure was dramatically destroyed accompanying severe oxidation and slight carbonization when the temperature increase up to 600 degrees C. The hardness of (W-10.5nm/B4C15.8nm)10 multilayer coating increases up to 37 GPa when the coating is heat treated below 500 degrees C, while it declined sharply when the coating is heat treated at 600 degrees C due to the a degradation of layered structure. In addition, the toughness of the multilayer coatings monotonously decreases with the increase of heat treatment temperature.