Abstract: Alkaloids were extracted five times from the dry papaya leaves by the solution of 90% ethanol contains1% HCl. And then, the extract was concentrated, filtered, and degreased by petroleum ether. The acidity was adjusted to pH8.0⁹.0 using concentrate NH3·H2O solution, and then extracted with excess chloroform. After purification of Silica gel column chromatography, alkaloids structural identification was performed with spectral methods (IR、MS、NMR) . The carpaine was isolated and identified.