The invention relates to a compound, namely, novel sesquiterpenoids as well as an extraction method and an application thereof, in particular to novel sesquiterpenoids extracted from a Mongolian medicine, namely, parnassia palustris. The chemical name of novel sesquiterpenoids is 3,4,9,12-tetraacetyl-6-benzoyl-10,13 epoxy-amine alkane. The extraction method of novel sesquiterpenoids comprises steps as follows: the parnassia palustris is taken, subjected to reflux extraction with ethanol and filtered, a filtrate is obtained, ethanol is recovered from the filtrate under reduced pressure, a total extract is obtained and extracted with dichloromethane, an extract and silica gel are blended, the mixture is sufficiently dried and subjected to chromatographic separation on a silicagel column and gradient elution through petroleum ether-acetone, eluates are mixed to form 8 fractions through thin-layer examination, the fraction 6 is separated with a chromatography method, and 3,4,9,12-tetraacetyl-6-benzoyl-10,13 epoxy-amine alkane is obtained. The novel sesquiterpenoids have the benefits as follows: the sesquiterpenoids with the anti-inflammatory activity, the antioxidant activity, other activities and particularly the antitumor acidity are obtained, the extraction method is simple and easy to implement, reagents are easy to obtain, material consumption is low, and the sesquiterpenoids are expected to relieve pain of numerous cancer patients, so that the cancer patients regain health.