Abstract: The T(d,n)~(4)He reaction was often used as a source of mono-energy neutrons with about 14 MeV in some experiments. Here, to measure the neutron fluence rate the associated particle method for the T(d,n)~(4)He reaction was used. The Au-Si detector was used to detect ~4He particles, and the Al-foil with 1.0 μm was used to shield the (deuterons) scattered from target. Through adjusting to device at some conditions, the system can discriminate clearly all kinds of particles and get a high precision neutron (fluence) rate.