We obtain effective exterion half angle of the anisotropic diffusion DLA clusters β= min βx, βy by analytical calculation. The hypothesis of Yu Jiang about β = maxβx,βy is modified and the formula of Hausdorff dimension D of the anisotropic diffusion DLA clusters varying with the anisotropic diffusion probability p is also modified. We also made simulation tests and find that the modified formula agrees well with experimental results. Finally, we compare our result with the numerical result of Jullien, and find a good coincidence when