The invention discloses a digital n-gamma real-time discrimination system. The system comprises a detector, a data acquisition card, an FPGA hardware platform and an upper computer. The detector is used for converting an n ray and a gamma ray into current signals. The data acquisition card is used for collecting the current signals and converting the current signals into digital pulse signals. TheFPGA hardware platform is used for calculating the centroid analysis providing parameters of the digital pulse signals through using an improved centroid algorithm according to the acquired digital pulse signals and is also used for determining a digital pulse signal amplitude and digital pulse signal time information according to the acquired digital pulse signals. The upper computer is used forstoring the centroid analysis providing parameters, the digital pulse signal amplitude and the digital pulse signal time information and drawing a n-gamma discrimination spectrogram according to storage information. By using the system of the invention, the improved centroid algorithm can be well realized, the n ray and the gamma ray can be distinguished, calculating complexity is low, a discrimination capability is high and a real-time discrimination requirement can be satisfied.