Abstract: A hierarchical algorithm was designed to solve strong cycle planning．Hierarchical algorithm is start with the target state,first,uses strong planning hierarchies,second,uses the weak planning hierarchies with the remaining states,and records the appropriate information,finally uses that information as a heuristic factor to search a strong cycle planning hierarchy in the result of weak planning hierarchies．After hierarchical states,information recorded can be used to get strong cycle planning solution directly．When larger state action pair exists,designed algorithm has high efficiency．When strong planning solution exists,it can owe better efficient,and can ensure a better strong cycle planning solution—strong planning solution obtained．Experiments show that designed algorithm can get strong cycle planning solution by fewer repeat searches,is better than the backward search by high efficiency.

Key words: Strong cycle planning,Hierarchical states,Nondeterministic planning,Intelligent planning