To improve the fatigue properties evaluation of the joint region of the fusion reactor blanket, the effect of the non-uniform distribution of the microstructure and strength on the fatigue properties of the electron beam weld joint of the F82H steel was investigated by the fatigue test and the numerical simulation of the deformation under the test. The fatigue life of the joint was approximately 10−20 % of that of the base metal. The fracture under the fatigue test occurred around the over-tempered heat affected zone (the region with the lowest hardness). One of the reasons of the shorter fatigue life of the joint could be the higher crack growth rate induced by the peak strain around the over-tempered heat affected zone due to the non-uniform deformation.