The Ti3Al/TC11 dual alloy specimen were prepared by laser solid forming, and then deformed by near isothermal forging with various deformation amounts. Afterwards, the effect of deformation amount on the microhardness and element diffusion of the transition zone and its two sides for Ti3Al/TC11 dual alloy specimen were investigated. The results show that after deformation, whatever the deformation amount is, the microhardness value of the transition zone and its two sides are decreased obviously, the differences in microhardness value along the same specimen are reduced significantly and the distribution is relatively homogeneously. In addition, the deformation amount has an obvious effect on the microhardness and element diffusion in the transition zone and its two sides. With the increase of deformation amount, all the value of the microhardness and its distribution homogeneity along the same specimen are increased; the concentration gradients of the alloying elements including Ti, Al and Nb on both sides of the transition zone are decreased, and they diffuse relatively sufficiently along the joining interface. The reason for that is because of larger deformation, the coarse columnar grains formed in laser solid forming are broken sufficiently, the grain boundaries of βphases are disappear, and the αand α2 phases show the fine and equiaxed shape.