Abstract:Objective: The pharmacognosy studies of the herb of Cymbopogon citratus (DC.) were systematically carried out. Methods: Macroscopical,microscopical and thin-layer chromatography(TLC) identification methods as well as moisture, total ash and acidinsoluble ash assay, determination of ethanol and ether extracts methods and assay of citral by HPLC were used for the identification and assay of the crude drug. Results: The main microscopical characteristics were bicollateral peltate vascular bundles, secretory cavity containing oil, nonglandular hair with single cell, small glandular hair, diacytic type stoma, beaded incrassate xylem parenchyma cells. The colored spot of citral was obviously shown in the TLC chromatogram. The moisture content in lemongrass is about 11.9%, the total ash is about 7.39% and the acid-insoluble ash is about 1.54%. The content of ethanolsoluable extract with hot maceration and the ether-soluable extract of volatile components are 9.04% and 2.20%, respectively. The average content of citral in lemongrass is about 1.32%. Conclusion: The research provided scientific basis for the identification, quality control and further exploitation of C. citratus.