Abstract: The neutron transport and thermo-mechanics of fast burst reactor are coupled with each other during the pulse excursion, and the coupled process has a decisive effect on the pulse properties. With the adiabatic assumption, a novel waveform approximation-based coupled computation method was introduced based on the fact that the temperature increase of fuel is always proportional to the total fission number. The mechanics modeling and the elastic wave equations’ computations were treated by commercially available finite element software ANSYS, and the neutronic model was determined by the point reactor kinetics equations. The mechanics and neutronic models were coupled with the reactivity feedback equation based on perturbation theory, and the parameters were adjusted until the computed rate waveform of fissions approximated that of the input temperature increase. The computed fission yield of Lady Godiva is in accordance with experimental result, and the proposed method has the potential to be used in future study and design of fast burst reactor.