It is quite different from those low to medium stacking fault energy face-centered cubic metals, Al and most its alloys are not applicable to twin-induced grain boundary engineering processing due to their high stacking fault energy. In order to optimize the grain boundary character distribution so as to remarkably better the properties of Al and its alloys, it is necessary at first to study the grain boundary plane distributions. In this work, two parallel high purity (99.99%) Al specimens, which were prepared by multi-directional forging followed by recrystallization annealing resulting in a homogeneous microstructure with averaged grain size around 20 μm, were separately processed by equal channel angular pressing (ECAP) and direct rolling (DR) with true strain ε≈2 followed by a recrystallization annealing at 360 ℃ for 8~90 min. Then, the grain boundary plane distributions were characterized by five-parameter analysis (FPA) based on stereology method and electron backscatter diffraction (EBSD). The results show that the grain boundary planes of the specimens as processed mainly orient on {111}, mostly corresponding to the <111> twist high angle boundaries. It is due to the energy minimum of {111}. The primary difference of grain boundary plane distributions between ECAP and DR specimens lies in the behaviors of grain boundary planes orienting onto {111}. For ECAP specimens, it is slow the grain boundary planes orienting onto {111}. However, for DR specimens, it is quite easy the grain boundary planes orienting onto {111}. Discussions pointed out, compared with ECAP deformation, DR deformation is more efficient for grain boundary plane orienting onto {111} in the subsequent recrystallization annealing and thus is more in favor of the optimization of grain boundary character distribution. It could be attributed to the development of <110>//ND textures during DR deformation which results in the fast grain growth in the subsequent recrystallization annealing.