Crosslinked metaplast influences char N₂ adsorption specific surface area (S_N2), and the influence changes with coal rank significantly. When crosslinked metaplast is adequate, planar polycyclic aromatic structures overlap tightly and S_N2 is small. When crosslinked metaplast content is small, S_N2 in crosslinked metaplast is larger than that in the coal matrix and takes a considerable proportion of total char surface area. Two exponents, k_{mat order} and k_{crlmet order}, representing order degrees of planar polycyclic aromatic structure arrangement in coal matrix and crosslinked metaplast, respectively, were introduced in the previous model for calculating the change of char surface area during coal pyrolysis. The previous model was extended to include predicting S_N2 of subbituminous and high-volatile bituminous coals, and was validated with 5 subbituminous coals, and 2 bituminous coals. The change of S_N2 with coal ranks and the transition characteristics between coal ranks can be predicted.