Abstract: This paper proposes a high efficient finite-difference time-domain (FDTD) parallel algorithmscheme with no exchanging data process in shared memory systems for the electrically large electromagneticproblems, which takes the advantage of shared memories of the general-purpose multicore processors architecture.FDTD parallel algorithm is realized by directly reading the field component data on the parallel boundary and themultithreaded programming technique is adapted to develop the parallel computation code of FDTD. Through aseries of the numerical tests, a way of the splitting region is proposed to implement the maximum parallelcomputational efficiency. It is verified that the proposed scheme is an idea parallel FDTD scheme in sharedmemory systems.