The continuum and slip choked Rows of low-density air through a narrow parallel-plate channel with adiabatic walls are investigated by means of finite-difference numerical calculation, experiment and analytical solution, In the numerical calculation based on two-dimensional compressible viscous boundary layer equations, the previous method is improved to achieve a higher pl precision of the choked state by decoupling the pressure term from momentum equation. The numerical results of discharge coefficient, pressure distribution and surface temperature distribution agree well with the experimental data. As the upstream tank pressure drops, the numerical results of friction coefficient and recovery factor approach the asymptotic values for the incompressible developed flow.