Synchronization operations make a huge expense for concurrent Java programs. This paper proposes an effective and precise static analysis algorithm for the redundant synchronization removal. The algorithm consists of two phases-basic analysis and inter-thread temporal analysis. Both phases take the effect of control flow relation and thread control relation into count. This paper also constructs a Java compiler-JTool and implements the algorithm on it. To deterministic single-threaded programs, the removal ratio reaches 100% and to multi-threaded programs, the removal ratio is higher than the existing analysis tools.