A neutron capture therapy system, comprising: a beam shaping assembly configured to adjust a beam energy spectrum and comprising an accommodating cavity and a moderator (14, 14') adjacent to an end of the accommodating cavity; a vacuum tube (30, 30') disposed in the beam shaping assembly; a target (31, 31'); a cooling device (20, 20') configured to cool the target; and at least one accommodating pipeline accommodating the cooling device, wherein the moderator is configured to moderate neutrons generated from the target (31, 31') to an epithermal neutron energy region, wherein a filler (40, 40', 40") is filled between the cooling device and an inner wall of the accommodating pipeline, wherein the cooling device comprises a first cooling portion (21, 21', 21") configured to cool the target, a second cooling portion (22, 22', 22") and a third cooling portion (23, 23', 23") located on two sides of the first cooling portion and connected with the first cooling portion respectively, the accommodating pipeline comprises a first accommodating pipeline (131, 131', 131") located between the target and the moderator, a second accommodating pipeline (132, 132', 132") and a third accommodating pipeline (133, 133', 133") located on two sides of the first accommodating pipeline and connected with the first accommodating pipeline respectively, the first cooling portion, the second cooling portion, and the third cooling portion are respectively contained in the first accommodating pipeline, the second accommodating pipeline, and the third accommodating pipeline, and characterised in that the filler is filled between the second cooling portion and an inner wall of the second accommodating pipeline and between the third cooling portion and an inner wall of the third accommodating pipeline, wherein the filler is a substance for reflecting or absorbing neutrons. a beam shaping assembly configured to adjust a beam energy spectrum and comprising an accommodating cavity and a moderator (14, 14') adjacent to an end of the accommodating cavity; a vacuum tube (30, 30') disposed in the beam shaping assembly; a target (31, 31'); a cooling device (20, 20') configured to cool the target; and at least one accommodating pipeline accommodating the cooling device, wherein the moderator is configured to moderate neutrons generated from the target (31, 31') to an epithermal neutron energy region, wherein a filler (40, 40', 40") is filled between the cooling device and an inner wall of the accommodating pipeline, wherein the cooling device comprises a first cooling portion (21, 21', 21") configured to cool the target, a second cooling portion (22, 22', 22") and a third cooling portion (23, 23', 23") located on two sides of the first cooling portion and connected with the first cooling portion respectively, the accommodating pipeline comprises a first accommodating pipeline (131, 131', 131") located between the target and the moderator, a second accommodating pipeline (132, 132', 132") and a third accommodating pipeline (133, 133', 133") located on two sides of the first accommodating pipeline and connected with the first accommodating pipeline respectively, the first cooling portion, the second cooling portion, and the third cooling portion are respectively contained in the first accommodating pipeline, the second accommodating pipeline, and the third accommodating pipeline, and characterised in that the filler is filled between the second cooling portion and an inner wall of the second accommodating pipeline and between the third cooling portion and an inner wall of the third accommodating pipeline, wherein the filler is a substance for reflecting or absorbing neutrons.