High performance computing is closely related to the development of numerical oceanic prediction. In order to enhance the intime property of the OVALS, this paper focuses on the parallelism of the OVALS system. In the process of parallelizing the ASSIMI part, the LayerFirstProcessorAllocation algorithm is proposed and the parallel I/O and global communication operations are implemented based on the LFPA algorithm. In the process of parallelizing the ASSssh part, an irregular domain decomposition algorithm based on the precondition is designed and implemented,which makes the computation load balancing of the parallel OVALS system. The numerical experiment shows that the parallel OVALS system gains a 17.45 speedup when running with 36 processes.