Natural essence is the typical kind of mixture of organic compounds which existed in the natural aromatic planes. The method of supercritical CO_2 extraction is one of the important methods for separation and refine of natural essence. Based on the retrieval and analysis of the Bibliographer, the methods of water-disitillation extraction, sametime-disitillation extraction and supercritical CO_2 extraction for the extraction of three typical kinds of natural substances in Zhejiang Province were evaluated exp...