A new pyridine alkaloid and six known compounds were isolated from the whole plant of Lysimachia patungensis Hand. Mazz. The structure of the new alkaloid, named patungensin. was characterized as(17R, E)-2-hydroxy-4,6-dimethoxy-17-acetoxy-cyclopentadeca-1, 3-diene[1,2-b]pyridine, and the six known compounds were identified as octacosanoic acid (1), palmic acid (2), stigmasterol (3), ardisiacrispin A (5), isorhamnetin 3-beta-D-galactopyranoside (6), and isorhamnetin 3-robinobioside (7), respectively.