Abstract: The effect of aluminized layer on tensile properties of a directional solidified Ni-based high-temperature alloy at different temperatures was studied. The results show that the aluminized layer decreased tensile strength and plasticity of the alloy at lower temperature (less than 870 ℃), but the reduction was fairly small. The aluminized layer had no effect on strength basically at 1 030 ℃, but the plasticity decreased obviously. The main reason for decreasing tensile properties was notch effect causing by the brittle fracture of aluminized layer at fairly lower tensile temperature.