The invention relates to an annular controllable isotope neutron source, which comprises a container main body, a sealing upper cover connected with the container main body in a sealing manner, an expansion link penetrating the sealing upper cover and stretching into the container main body, and a radiating cavity. A sealing cavity is formed by the container main body and the sealing upper cover; a rotating disc is fixed on one end, located outside the sealing cavity, of the expansion link; a carrier ring fixing sheet is fixed on one end, located inside the sealing cavity, of the expansion link; the carrier ring fixing sheet is fixedly provided with n alpha-particle emission nuclide carrier rings; the radiating cavity is fixed on the center of the bottom of the container main body; n+1 beryllium rings are also fixed on the bottom of the container main body; the n alpha-particle emission nuclide carrier rings are located between adjacent beryllium rings sequentially at intervals; an alpha-particle emission nuclide layer covers the alpha-particle emission nuclide carrier rings. The annular controllable isotope neutron source solves the technical problem of the existing uncontrollable isotope neutron source, realizes generation and disappearance of the neutron through controlling two nuclides needed in (alpha, n) nuclear reaction to lean close to each other and be separated from each other, and realizes the controllable purpose.