The microstructure and mechanical properties of EAM16MND5 steel by electrical additive manufacturing were investigated by electrical additive manufacturing in eight different heat treatment parameters by the number of thermal cycles,the temperature,holding time and the kind of heat treatment factors. The experimental results showed that the strength of the material was changed less in different thermal cycles or the temperatures of heat treatment after stressrelieving heat treatment. The effect of the holding time on simulated stress relieving heat treatment was less for material strength,but more for impact ductility,and the impact ductility was more excellent for the material with second stress relieving heat treatment than the first. The carbide was diffusing to the intergranular and assembling during stress relieving heat treatment and simulated stress relieving heat treatment.