To reduce the total time for aligning all laser beams of an inertial confinement fusion (ICF) laser facility at the target area, an alignment route optimization method is for the alignment method that based on the invariant sub-area configuration of the alignment sensor. The goal is to minimize the sum of the angle displacements of those reflecting mirrors which make contributions to the total alignment time. It can be implemented by optimizing the angle between the center of the preparative sub-area and that of the target sub-area. The optimization process is demonstrated through an example that one configuration of the final optics assemblies is considered and the expected aligning position is at the center of the target chamber. The estimations of the total alignment time show that the proposed method results in a much shorter time compared with the common serial alignment method. If the distance between the center of the preparative sub-area and the center of the target sub-area is 1 mm, the total time is reduced to 0.518 times of that adopting a common serial alignment method.