The invention relates to the field of Chinese medicine extraction and separation, in particular to a special amide alkaloid compound which is extracted, separated and identified from portulaca oleracea and an extraction and separation method thereof. The molecules of the new alkaloid compound are C24H39NO7 in sequence, and the new alkaloid compound is named after oleraciamide C. According to the extraction and separation method of the new alkaloid compound, 50% ethyl alcohol reflux extraction, macroporous absorbent resin chromatography, ethyl acetate extraction, polyamide column chromatography, silica column chromatography, Sephadex LH-20 purification and ODS medium-pressure column separation and purification are adopted in sequence, and therefore the new special amide alkaloid compound is successfully extracted and separated. The amide alkaloid compound has the effects of resistance to inflammation and tumors and neuroprotection. The amide alkaloid compound and salt or derivatives thereof can serve as primers of other compounds and raw materials for development of new drugs and research on pharmacological activity, and is used for preparing medicine or health-care products resisting inflammation and tumor and having neuroprotection.