A neutron capture therapy system comprising: a neutron generating device comprising an accelerator and a target, wherein a charged particle beam generated by acceleration of the accelerator interacts with the target to generate a neutron beam, wherein the target comprises: an acting layer for interacting with the charged particle beam to generate the neutron beam, an oxidation resistant layer, a backing layer for supporting the acting layer, and a heat dissipating layer including a tubular member composed of tubes arranged side by side; and a beam shaping assembly comprising: a moderator for decelerating the neutron generated from the target to the epithermal neutron energy region, a reflector surrounding the moderator, wherein the reflector directs the deviating neutron back to the moderator to enhance intensity of the epithermal neutron beam, a thermal neutron absorber provided to absorb thermal neutrons to avoid overdosing in superficial normal tissue during therapy, a radiation shield arranged at the rear of the reflector around a beam exit for shielding leaking neutrons and photons so as to reduce dose of the normal tissue in non-irradiated area, and said beam exit; wherein the shape of the cross section of the entirety formed by the backing layer, the acting layer, and the oxidation resistant layer perpendicular to the center line of the tube is consistent with the outer surface contour of a side of the tubes connecting with the backing layer, the acting layer, and the oxidation-resistant layer and it is arc-shaped, wherein said acting layer on each tube covers at least 1/4 of an outer circumference of said tube. a neutron generating device comprising an accelerator and a target, wherein a charged particle beam generated by acceleration of the accelerator interacts with the target to generate a neutron beam, wherein the target comprises: an acting layer for interacting with the charged particle beam to generate the neutron beam, an oxidation resistant layer, a backing layer for supporting the acting layer, and a heat dissipating layer including a tubular member composed of tubes arranged side by side; and a beam shaping assembly comprising: a moderator for decelerating the neutron generated from the target to the epithermal neutron energy region, a reflector surrounding the moderator, wherein the reflector directs the deviating neutron back to the moderator to enhance intensity of the epithermal neutron beam, a thermal neutron absorber provided to absorb thermal neutrons to avoid overdosing in superficial normal tissue during therapy, a radiation shield arranged at the rear of the reflector around a beam exit for shielding leaking neutrons and photons so as to reduce dose of the normal tissue in non-irradiated area, and said beam exit; wherein the shape of the cross section of the entirety formed by the backing layer, the acting layer, and the oxidation resistant layer perpendicular to the center line of the tube is consistent with the outer surface contour of a side of the tubes connecting with the backing layer, the acting layer, and the oxidation-resistant layer and it is arc-shaped, wherein said acting layer on each tube covers at least 1/4 of an outer circumference of said tube. a backing layer for supporting the acting layer, and a heat dissipating layer including a tubular member composed of tubes arranged side by side; and a beam shaping assembly comprising: a moderator for decelerating the neutron generated from the target to the epithermal neutron energy region, a reflector surrounding the moderator, wherein the reflector directs the deviating neutron back to the moderator to enhance intensity of the epithermal neutron beam, a thermal neutron absorber provided to absorb thermal neutrons to avoid overdosing in superficial normal tissue during therapy, a radiation shield arranged at the rear of the reflector around a beam exit for shielding leaking neutrons and photons so as to reduce dose of the normal tissue in non-irradiated area, and said beam exit; a moderator for decelerating the neutron generated from the target to the epithermal neutron energy region, a reflector surrounding the moderator, wherein the reflector directs the deviating neutron back to the moderator to enhance intensity of the epithermal neutron beam, a thermal neutron absorber provided to absorb thermal neutrons to avoid overdosing in superficial normal tissue during therapy, a radiation shield arranged at the rear of the reflector around a beam exit for shielding leaking neutrons and photons so as to reduce dose of the normal tissue in non-irradiated area, and said beam exit; wherein the shape of the cross section of the entirety formed by the backing layer, the acting layer, and the oxidation resistant layer perpendicular to the center line of the tube is consistent with the outer surface contour of a side of the tubes connecting with the backing layer, the acting layer, and the oxidation-resistant layer and it is arc-shaped, wherein said acting layer on each tube covers at least 1/4 of an outer circumference of said tube.