Authors consider the Hausdorff dimension of the divergence set for asymptotically additive sequence in a class of non-uniformly expanding systems.Using techniques of constructing "Moran set" and joining n-level Bernoulli measures, they prove that the Hausdorff dimension of the divergence set in this class of systems has "dichotomy", i.e., if the divergence set is not empty set, it will has full Hausdorff dimension.