Kinetic Monte Carlo (KMC) simulation can be used to simulate the radiation effects and defect diffusion of reactor materials in nuclear power plants, which is helpful to understand and predict how microstructures and mechanical properties evolve under irradiation. We present a parallel simulation method of vacancy diffusion based on synchronous sub-lattice (SL) algorithm. We adopt a dynamic communication data update method and an adaptive time synchronization method to decrease communication frequency and load so as to achieve both accuracy and parallel efficiency. Simulation results show that the serial implementation by the SL algorithm saves the total execution time by 60.31% in comparison with the original algorithm, and the parallel implementation achieves 39X speedup with 80 cores. The algorithm also performs well on large scale problems.