Disclosed is a beam shaper (10) for neutron capture therapy, including a beam entrance (11), a target (12), a moderator (13) adjoins to the target (12), a reflector (14) surrounding the moderator (13), and a beam exit (17), wherein the moderator (13) may be replaced to adjust the retarding capacity of the moderator (13) for neutrons. The beam shaper (10) for neutron capture therapy only needs the actual requirements of beam neutron energy region, neutron beam flux and other indexes, according to the tumour, to select different materials of the moderator (13) to adjust the slow capacity of neutrons, wherein the same medical equipment can be used to treat different patients, and same has a simple structure and a strong applicability.
