From the tuber of Alisma orientale (Sam.) Juzep. (Alismataceae), twenty-four compounds were isolated, including six (1, 2, 3, 10, 14, and 17) that were not yet characterized. Spectroscopic investigations (IR, UV, HRESIMS, and NMR) were used to clarify their structures, and the ECD spectra of two compounds (8 and 9) were interpreted to identify their absolute configurations. Through an apoptotic signaling pathway, compounds 7, 15, 17, and 19 decreased the level of apoptosis in lung epithelial cells, indicating that they may have potential anti-pulmonary fibrosis (anti-PF) activity.