We investigated the substitution effects of Al3+ for Cr3+ on the structure and magnetic, properties of delafossite oxide CuCrO2, which possesses a quasi-2D Heisenberg triangular antiferromagnetic (AFM) lattice. The lattice parameters was found to vary according to the Vegard’s rule. We also found that the large local lattice distortion, caused by the nonmagnetic dopant with different radii between magnetic and nonmagnetic ions, affects the samples significantly. Magnetization and specific heat measurements indicated that AFM ordering is diluted by the substitution of nonmagnetic Al3+ for Cr3+ (S = 3/2). <alternatives> [...] </alternatives>