Most P2‐type layered oxides exhibit a large volume change when they are charged into high voltage, and it further leads to bad structural stability. In fact, high voltage is not the reason which causes the irreversible phase transition. There are two internal factors which affect structural evolution: the amount and distribution of Na ions retained in the lattice. Hereon, a series of layered oxides Na2/3MnxNix−1/3Co4/3−2xO2 (1/3≤x≤2/3) were synthesized. It is observed that different components have different structural evolutions during the charge/discharge processes, and further researches find that the distribution of Na ions in layers is the main factor. By controlling the distribution of Na ions, the phase transition process can be well controlled. As the referential component, P2‐Na2/3Mn1/2Ni1/6Co1/3O2 cathode with uniform distribution of Na ions is cycled at the voltage window of 1.5–4.5 V, which exhibits a volume change as low as 1.9 %. Such a low strain is beneficial for cycling stability. The current work provides a new and effective route to regulate the structural evolution of the promising P2‐type layered cathode for sodium ion batteries. The number and distribution of Na ions retained in lattice are two internal factors which affect structural evolution. Na ions can support the lattice structure like pillars, by regulating the distribution of Na ions, the process of phase transition can be controlled. As a result, the cathode can offer as high capacity as possible without obvious phase transition.