The invention provides a parallel optimization method of DOACROSS cycle. On the basis of ensuring the correctness of data dependence, by adding a state matrix and a ready node queue, the synchronous operation is transformed into the enqueue / dequeue operation of the ready node queue. The invention realizes the dynamic task assignment of each thread to the computing area, that is, on the basis of guaranteeing the wave front advance, a certain thread will no longer be fixed to the execution of a certain calculation area, but always in time to implementation of those blocks which satisfy executable conditions, and multi-dimensional block partitioning is also realized. The theoretical execution time of the method of the present invention is shorter than the theoretical execution time of the existing three strategies and is close to the optimal execution time.