The invention discloses a nuclear fission chain reaction dynamic demonstrator, which comprises a bracket, a glass container, a bottom plate, a goal opening, a swing cylinder, an air pump, an air blowing port, a programmable controller, a splitting neutron ball and an impacting neutron ball , the glass container is arranged on the support, the bottom plate is arranged under the glass container, the atomic nucleus model map arranged together is arranged on the bottom plate, a notch is arranged on the bottom plate corresponding to the atomic nucleus model map, and the split neutron ball is placed in the notch, The blowing port is arranged at the lower side of the glass container, the shaft of the swing cylinder is supported on the bottom side of the bottom plate, the ball opening is located at the top of the glass container, and the swing cylinder is connected with the programmable controller. The demonstrator of the invention can dynamically demonstrate nuclear fission chain reaction, and is convenient for science popularization and education of nuclear fission knowledge.