Abstract: A brief theoretical principle of the production of 14 MeV neutrons from thermal neutrons has been given.The ⁶LiD convertors rely on the absorption of a thermal neutron resulting in a triton which interacts with deuterium producing a 14 MeV neutron.The calculation and analysis model of 14 MeV neutron flux in the convertor have considered the neutron flux disturbance of convertor to irradiation channel and the leakage of T in ⁶LiD converter.The calculation and analysis model of effective yield of 14 MeV neutron,which generated from thermal neutron,has been established.The results show that the optimal thickness of ⁶LiD is 0.85 mm,and effective yield(Y) of thermal neutron converting 14 MeV neutron is 3.18×10^-4.