<jats:title>Abstract</jats:title><jats:p>A new lycopodine alkaloid, 15<jats:italic>α</jats:italic>‐methyllycopodane‐5<jats:italic>β</jats:italic>,6<jats:italic>β</jats:italic>‐diol <jats:italic>N</jats:italic>‐oxide (<jats:bold>1</jats:bold>), was isolated from the whole plants of <jats:italic>Phlegmariurus yunnanensis</jats:italic> <jats:sc>Ching</jats:sc>, together with the two known alkaloids 15<jats:italic>α</jats:italic>‐methyllycopodane‐5<jats:italic>β</jats:italic>,6<jats:italic>β</jats:italic>‐diol (<jats:bold>2</jats:bold>) and lycoposerramine H (<jats:bold>3</jats:bold>), and four serratene‐type triterpenoids, serratenediol‐3‐acetate (<jats:bold>4</jats:bold>), serratenediol (<jats:bold>5</jats:bold>), lycocryptol (<jats:bold>6</jats:bold>), and serratriol (<jats:bold>7</jats:bold>). Their structures were elucidated on the basis of spectroscopic analyses, including HR‐ESI‐MS, <jats:sup>1</jats:sup>H‐ and <jats:sup>13</jats:sup>C‐NMR, DEPT, <jats:sup>1</jats:sup>H,<jats:sup>1</jats:sup>H‐COSY, HSQC, HMBC, and NOESY.