A fast neutron detector using the EJ301 scintillator was manufactured for study on detecting fast neutrons and gamma-rays. Detector characteristics include the energy linearity, the efficiency response and the neutron/gamma discrimination were guaranteed for neutron detection in the energy range from 50 to 3000 keVee. The ability discrimination of neutrons/gamma-rays of the detector was evaluated by the charge comparison (CC) method using an 252Cf source. The total efficiencies when measured on 22Na, 137Cs, 60Co and 252Cf sources were obtained 17.8%, 3.9%, 9.8% and 14.8%, respectively. The Figure of Merit (FoM) values of CC method were 0.4–1.55 for the range of energy 50–1000 keVee (keV electron equivalent).