<jats:title>Abstract</jats:title><jats:p>Two new C<jats:sub>20</jats:sub>‐diterpenoid alkaloids named naviculine A (<jats:bold>1</jats:bold>) and naviculine B (<jats:bold>2</jats:bold>), were isolated from <jats:italic>Aconitum naviculare</jats:italic> <jats:sc>Stapf</jats:sc>. Their structures were established by spectral methods, especially 2D‐NMR spectra (<jats:sup>1</jats:sup>H,<jats:sup>1</jats:sup>H‐COSY, HMQC, HMBC, and NOESY) and DFT methods (at the B3LYP/6‐311++G(2d,p)//B3LYP/6‐31G(d) level), respectively. They were assayed for their anti‐HIV‐1 activity.