B4C/6061Al neutron absorber materials with four volume fractions(0vol%，20vol.%,30vol.% and 40vol.%) were successfully fabricated by vacuum hot pressing and following hot rolling(VHPR) in atmospheric environments. Microstructure and interface behavior were studied. Besides，the tensile strength, fracture behavior and strengthening mechanism of neutron absorber materials were also investigated. The results showed that the space network of matrix was constructed by 6061Al.Besides, the interface reached metallurgical bonding state and the thickness of the diffusion layer was about 5um. With the increase of the volume fraction of B4C, some small B4C particles agglomerated locally, and the tensile strength first increased and then decreased.The main fracture behaviors were interface fracture and the cleavage fracture of B4C particles. After multi-pass hot cross rolling, the grains of the matrix materials were refined and the distribution of B4C particles was also improved; besides, internal defects were reduced and plastic deformation zones around B4C particles also formed after hot cross rolling.