Within the scheme of the weakest bound electron potential model theory, the
concept of spectral-level-like series is presented by reasonably classifyi
ng the Rydberg energy level of atom Al. Based on this concept, the regulari
ties of the Rydberg energy revels are systematically studied. The deviation
s of the calculated values from the experimental values are generally about
several percent of 1 cm, which is of high accuracy.