The invention discloses a method for 
welding tantalum layers to six faces of a 
tungsten block in a 
diffusion manner. The method comprises the steps that an outer wrapping sleeve is made of at least one of 
titanium, iron and 
molybdenum and is provided with a cavity for containing the 
tungsten block, spacer sheets and 
tantalum sheets are sequentially laid on the inner wall of the cavity, and then the 
tungsten block is placed in the cavity; 
tantalum sheets and spacer sheets are sequentially laid on the surface of the part, on the end face of the outer wrapping sleeve, of the tungsten block, 
metal sheets are used for covering, and 
electron beam 
welding is carried out on the 
metal sheets and the outer wrapping sleeve under the vacuum condition; then hot isostatic 
pressure diffusion welding is carried out; and the outer wrapping sleeve is removed after welding is finished. According to the method, the tantalum sheets and the tungsten block are located through the outer wrapping sleeve, the step of manufacturing a tantalum box through 
electron beam welding is omitted, no air suction material is needed for wrapping, the technology is simple, and cost is low. Due to the spacer sheets, after 
diffusion welding is finished, products can be taken out very conveniently, simpleness and easy operation are achieved, the requirement for efficiently producing tantalum-tungsten composite materials in a batch manner can be met, and a basis is laid for research and wide application of 
spallation neutron sources.