The ABC spectral radius of a graph G, denoted by? (G), has attracted more p and more attentions. In this paper, we prove that (G) + 2m - n + 1{-2 }, where G is a connected graph with n vertices, m edges, and maximum degree? . As applications, we reproduce the upper bounds of ABC spectral radius for connected graphs, trees, unicyclic graphs, and bicyclic graphs.
Lin et al. (Thu,) studied this question.