Coarsening is a metallurgical process that is related to solute transmission and system energy decrease. However, for the coarsening behavior of the L12 precipitate in high-entropy alloys, the influence of moving boundary is still an open question. Here, we found the moving boundary accelerates the discontinuous coarsening of L12 phase. The multiple defects-accelerated diffusion and continual particle-capturing ability of the moving boundary provide a high-efficiency solute transport for the fast-coarsening kinetics of L12 phase. In addition, a boundary-encountered assisted precipitate formation mechanism is also validated in the recrystallized area.