The finite-difference time-domain (FDTD) has been commonly used for electromagnetic field simulation. However, parallelization of FDTD usually consumes large amount of memories
and very long time, especially when the target domain is in 3D space. And the communication
between calculating cores can be the bottleneck of the parallelize performance. In this paper we
propose an optimized method named Crossing Calculation Method to accelerate FDTD simulation.
Crossing Calculation Method can overlap the communication time which includes data
exchanging time and synchronization time between neighborhood calculating nodes. The result
shows that Crossing Calculation Method has linear speedup along with the increasing of calculating cores.