Abstract: In order to detect high energy neutron and obtain neutron energy spectrum information, a set of neutron detection system based on plastic scintillator fiber and multiplexing technology was designed. The gradient arrayed detector was used to sense the energy and direction of the incident neutron. The multiplexing data acquisition and reading unit received the detector output signal and generated a trigger signal, which was processed and then uploaded to the host computer. The data acquisition and readout system realized real-time communication via Ethernet. The host computer program was developed based on the LabWindows/CVI software platform, and it realized the read and save of data and the real-time display of the system running state parameter information. The neutron simulation source was tested on site. The result shows that the neutron detection system meets the design requirement and can realize the measurement of neutron energy and incident direction.