Abstract: The neutron monitoring is a regular project of nuclear involving places. It is particularly important to improve the calibration technology of radiation monitor for guaranteeing the quality of radiation monitoring. It is difficult for neutron monitor calibration in some circumstance as where the neutron monitor is restricted by the site so that it cannot be moved to trace to the upper grade national measurement standards. To solve this kind of problem, a radiation monitor on-site calibration technology study was put forward. In order to get single-energy neutron source and realize the radiation monitor on-site calibration technology, neutron source characteristics and structure characteristics of D-T neutron tube were analyzed, and the effects of typical shielding materials with different energy neutrons were analyzed by Monte Carlo method. The typical shielding materials were combined in different methods, and the optimum shielding scheme was obtain. On this basis, collimator and filter cone structures were designed and the filtering effects of different materials were simulated by Monte Carlo. The result shows that a number of monoenergetic neutrons with good monochromaticity such as 14.1 MeV, 0.18 MeV and thermal neutron can be obtained, which provides multiple monoenergetic neutron sources for the on-site calibration.