In this study, the chemical constituents of the aerial parts of Archidendron bauchei (Jack) I. Niels have been investigated for the first time. Ten antioxidant compounds have been isolated and identified from the extracts, in which the amounts of methyl gallate and quercetin are fairly large with around 1.588 ± 0.014 and 3.145 ± 0.049 mg/g, respectively. In addition, the antioxidant potential of all extracted fractions and the isolated compounds were evaluated through DPPH radical scavenging. Moreover, the antioxidant capacity of some selected phenolic compounds was also computationally predicted using density functional theory. It was found that there is a consistency in both theoretical and experimental approaches for evaluating the antioxidants of the phenolic compounds extracted from A. bauchei.