Is there any implementation of AO* algorithm? I'm trying to solve And-Or Graph, and I find AO* algorithm can handle it. Someone said it's already used in AI, but I can't find it in detail.

Have it implemented? Or it's just a pseudocode that can't realized? If it exists, where can I find it? Or any suggestions to help me to implement it? I'm really appreciate your help.
I cannot point you towards an existing implementation, but I am pretty confident that it is not too hard to implement yourself. I suggest you to have a look at this paper by Nau, Kumar and Kanal, which has detailed pseudocode for AO* and other related algorithms such as A* and branch and bound. In particular, have a look into Section 7 of that paper and the procedures they call P8 and P9.