The invention discloses a monoterpene compound as well as a preparation method and application thereof. The monoterpene compound is obtained by taking chenopodium ambrosioides leaves as a raw material, extracting extract, extracting with an organic solvent, carrying out silica gelcolumn chromatography, carrying out Sephadex LH-20 column chromatography and carrying out high pressure liquid chromatography separation, wherein the molecular formula of the compound is C10H16O2, the compound is named 4-hydroxy-4-isopropyl-2-methyl-2-cyclohexene-1-one, and the compound has a structure (described in the specification). The preparation method comprises the following steps: by taking the chenopodium ambrosioides leaves as the raw material, extracting the extract, extracting with the organic solvent, carrying out the silica gelcolumn chromatography, carrying out the Sephadex LH-20 column chromatography and carrying out the high pressure liquid chromatography separation, so that the monoterpene compound is obtained. The application is namely application of the monoterpene compound in preparation of a drug used for preventing and/or inflammation. In vitro anti-inflammation activity tests are carried out on the monoterpene compound, and experimental results show that the monoterpene compound has good effect of inhibiting lipopolysaccharide (LPS)-induced mouse macrophage (RAW264.7) from producing nitric oxide (NO) and can provide a lead compound with application value for medical industry.