The semi-solid compression deformation behavior of the AZ91D alloy with non-dendritic structure, which was obtained under the semi-solid isothermal treatment condition of 570 degrees C x60min, was studied by means of Gleeble- 1500 thermal-mechanical simulator. When the compression strain was lower than 0.7, along with the compression strain increasing, the compression stress firstly increased rapidly, then decreased rapidly, and finally kept a constant stress level gradually. Under the condition of different deformation temperatures and deformation rates, the maximum compression stress was obtained simultaneously when the compression strain value was 0.025 approximatively. Furthermore, when the deformation rate kept a constant, the compression stress decreased along with the deformation temperature increasing, and when the deformation temperature kept a constant, the compression stress increased along with the deformation rate increasing.