The invention belongs to the technical field of medicinal chemistry and medicine, and relates to a novel organic matter enantiomer pure octadecanoic acid (OA) extracted from natural food, a preparation method and uses thereof. According to the present invention, the test results show that OA has good pharmacological activity and pharmacokinetic properties in the fields of blood glucose lowering, blood fat regulating, inflammation resistance, insulin sensitivity enhancement and the like, and can further be used as the active ingredient to preparing pharmacological compounds for treatment of various diabetic complications including but being not limited to atherosclerosis, cardiovascular and cerebrovascular diseases, lower extremity atherosclerosis, diabetic foot, diabetic peripheral neuropathy, diabetic nephropathy, diabetic cognitive dysfunction, diabetic retinopathy and the like; the preparation method has characteristics of relatively simple operation, easy industrial production andthe like; and the organic matter enantiomer pure OA of the present invention has significantly enhanced blood glucose lowering activity, significantly enhanced blood fat regulating activity and significantly enhanced anti-inflammatory activity compared to the un-modified OA, and further ha excellent pharmacokinetics. The structure of the organic matter enantiomer pure OA is defined in the specification.