Lung adenocarcinoma is the most common type of lung cancer. With a rise in new cases worldwide each year, early diagnosis and treatment are very important. Network pharmacology provides the effective way to evaluate poly-pharmacological effects and anticancer molecular mechanisms of drugs. The aim of the present study was to explore the anti-tumor mechanism of ethyl acetate extract of Wenxia Changfu Formula (WFEA) in lung adenocarcinoma by using analytical chemistry, network pharmacology and molecular biology. A total of 193 compounds were identified from WFEA, mainly including esters, phenols, ketones and alkaloids. Totally, 374 targets were regarded as potential targets of WFEA against lung adenocarcinoma. Interestingly, PI3K-AKT was found to be one of the significantly enriched signaling pathways of targets of WFEA against lung adenocarcinoma. AKT1, MMP3, CASP3 and BCL2 had strong binding effect with compound molecules of WFEA. Some combinations with the best docking binding were identified, including quercetin/oleanolic_acid/emodin/aloe_emodin/catechin-AKT1 and quercetin-MMP3. In lung adenocarcinoma cells, the WFEA inhibited the proliferation, migration and invasion, and promoted the apoptosis. Moreover, the WFEA inhibited the mRNA expression of MMP3 and Bcl-2 and promoted the mRNA expression of Caspase3. In addition, WFEA inhibited the protein phosphorylation of AKT and PI3K. The WFEA had a significant inhibitory effect on lung adenocarcinoma cells, which could inhibit cell proliferation, invasion and metastasis, and induce cell apoptosis. The mechanism of action of WFEA may be involved in the regulation of the PI3K-AKT signaling pathway in the lung adenocarcinoma.