A hexamethylenediamine synthesis system comprises a feeder, a reactor and a distributor, wherein the reactor comprises a plurality of material mixing pipelines, a plurality of material synthesis pipelines and a separator, an inner cavity of the separator comprises a gas-liquid separation zone, a liquid-solid separation zone and a conical sedimentation zone, a material mixing device is arranged ineach material mixing pipeline, and the feeder is connected with the material mixing pipelines. The upper end of each material mixing pipeline is communicated with the gas-liquid separation zone, the lower end of each material mixing pipeline is communicated with the feeding end of the distributor, and each material synthesis pipeline is wrapped with a cooling medium jacket. A spiral mixing deviceis arranged in each material synthesis pipeline, the upper end of each material synthesis pipeline is communicated with the gas-liquid separation zone and located above the corresponding material mixing pipeline, and the lower end of each material synthesis pipeline is communicated with the discharging end of the distributor. A hydrogen inlet is formed in each material synthesis pipeline, an exhaust pipeline is arranged at the top of the gas-liquid separation zone, the liquid-solid separation zone is provided with a hexamethylenediamine discharge pipeline, and the conical sedimentation zone iscommunicated with the feeding end of the distributor through a return pipeline.