By using a distorted-wave Born exchange ( DWBE ) approximation method inclu
ding the relativistic correction, we calculated the direct ionization and e
xcitation autoionization cross sections of eight Na-like ions. Based on the
calculated results, we present two empirical formulas with high accuracy f
or calculating direct ionization and excitation autoionization cross sectio
ns. Our results are in good agreement with the experiment data and other th
eoretical values.