The analysis and computation of chemical non-equilibrium hypersonic wakes are important tasks of reentry aerodynamics. This paper，using axial equations, successfully climinates the axial sigularity in governing equations. Using central differences secret scheme with two rand accuracy，it has solved the parabolic N-S equations and obtained numerical solutions of wakes at 20km and 60km，The results show that the effect of oxygen-electron attachment processes on electron density in far wakes is important.