A total RNA extraction method is introduced, the main extraction reagents used in this method are SDS, chloroform and Tris-phenol, and the reagents of RNA precipitation are LiCl and ethanol. The total RNAs were successfully extracted from Tamarix androssowii(woody plant), Puccinellia tenuiflora (herbage), Saperda populnea (insect), Saccharomyces cerevisiae(fungi) and White-rot fungi by using this method. The total RNA extracted by this method produced clear bands, and the ratios of A260/A280 were above 1.8. The analysis of RNA precipitation efficiency showed that total RNA could be deposited completely in 10 minutes by the cooperation of LiCl and ethanol. At the same time, high purity DNA also can be isolated by this method, the quality of extracted RNA can meet the need of some molecule biology work requiring high quality RNA, such as cDNA library construction, labeling probes for gene chip and RT-PCR. The above described shows this method for RNA isolation can be widely applied.