In a previous study, our team found that ASPP2 overexpression increases the sensitivity of liver cancer cells to sorafenib. ASPP2 is an important target in the study of drug therapy for hepatocellular carcinoma. In this study, we demonstrated that ASPP2 altered the response of HepG2 cells to usnic acid (UA) by using mRNA sequencing and CyTOF. CCK8 assay was used to detect cytotoxicity of UA on HepG2 cells. Annexin V-RPE assay, TUNEL assay, and cleaved caspase 3 assay were performed to examine the apoptotic cell death induced by UA. Transcriptomic sequencing and a single-cell mass cytometry were used to analyze the dynamic response of HepG2shcon and HepG2shASPP2 cells to UA treatment. We have demonstrated that UA could inhibit proliferation in HepG2 cells in a concentration-dependent manner. Apoptotic cell death was significantly induced by UA in HepG2 cells, while knocking down ASPP2 could increase the resistance of HepG2 cells to UA. Data from mRNA-Seq indicated that knockout of ASPP2 in HepG2 cells affected cell proliferation, cycle, and metabolism. ASPP2 knockdown resulted in increased stemness and decreased apoptosis of HepG2 cells under the action of UA. CyTOF analysis confirmed the above results, ASPP2 knockdown increased oncoproteins in HepG2 cells and altered response patterns of HepG2 cells to UA. Our data suggested that the natural compound UA could inhibit liver cancer HepG2 cells; meanwhile, ASPP2 knockdown could affect response patterns of HepG2 cells to UA. The above results indicate that ASPP2 could be a research target in the chemoresistance of liver cancer.