A neutron capture therapy system comprising: an accelerator, wherein the accelerator is adapted to generate a charged particle beam; a neutron generator, wherein the neutron generator is adapted to generate a neutron beam after being irradiated by the charged particle beam; a vacuum tube, wherein the vacuum tube is adapted to transport charged particles accelerated by the accelerator to the neutron generator; a beam shaping assembly, wherein the beam shaping assembly comprises a moderator and a reflector surrounding the moderator, the moderator being adapted to moderate the neutrons generated by the neutron generator to a preset spectrum and the reflector being adapted to lead the deflected neutrons back to increase the neutron intensity within the preset spectrum; and a collimator, wherein the collimator is adapted to concentrate the neutrons generated by the neutron generator, characterized in that the neutron capture therapy system further comprises a plurality of beam energy spectrum adjusting members capable of adjusting spectrum of the charged particle beam, and different members of the beam energy spectrum adjusting members have different spectrum adjustment effects on the charged particle beam, wherein the spectrum of the neutron beam is changed by changing the spectrum of the charged particle beam; wherein the vacuum tube is provided with an accommodating portion under the neutron generator, and the beam energy spectrum adjusting members are accommodated in the accommodating portion; and the beam energy spectrum adjusting members are connected with a driving mechanism capable of moving the beam energy spectrum adjusting members; so that when the driving mechanism controls the beam energy spectrum adjusting members to move to the front of the neutron generator, the charged particle beam first irradiates the beam energy spectrum adjusting members and then the neutron generator; when the driving mechanism controls the beam energy spectrum adjusting members to be accommodated in the accommodating portion and not in front of the neutron generator, the charged particle beam directly irradiates the neutron generator; wherein when a member of the beam energy spectrum adjusting members is located in the vacuum tube and is in front of the neutron generator, the spectrum of the charged particle beam is adjusted by said member. an accelerator, wherein the accelerator is adapted to generate a charged particle beam; a neutron generator, wherein the neutron generator is adapted to generate a neutron beam after being irradiated by the charged particle beam; a vacuum tube, wherein the vacuum tube is adapted to transport charged particles accelerated by the accelerator to the neutron generator; a beam shaping assembly, wherein the beam shaping assembly comprises a moderator and a reflector surrounding the moderator, the moderator being adapted to moderate the neutrons generated by the neutron generator to a preset spectrum and the reflector being adapted to lead the deflected neutrons back to increase the neutron intensity within the preset spectrum; and a collimator, wherein the collimator is adapted to concentrate the neutrons generated by the neutron generator, characterized in that the neutron capture therapy system further comprises a plurality of beam energy spectrum adjusting members capable of adjusting spectrum of the charged particle beam, and different members of the beam energy spectrum adjusting members have different spectrum adjustment effects on the charged particle beam, wherein the spectrum of the neutron beam is changed by changing the spectrum of the charged particle beam; wherein the vacuum tube is provided with an accommodating portion under the neutron generator, and the beam energy spectrum adjusting members are accommodated in the accommodating portion; and the beam energy spectrum adjusting members are connected with a driving mechanism capable of moving the beam energy spectrum adjusting members; so that when the driving mechanism controls the beam energy spectrum adjusting members to move to the front of the neutron generator, the charged particle beam first irradiates the beam energy spectrum adjusting members and then the neutron generator; when the driving mechanism controls the beam energy spectrum adjusting members to be accommodated in the accommodating portion and not in front of the neutron generator, the charged particle beam directly irradiates the neutron generator; wherein when a member of the beam energy spectrum adjusting members is located in the vacuum tube and is in front of the neutron generator, the spectrum of the charged particle beam is adjusted by said member.