Abstract: Total RNA was isolated from Siraitia grosvenorii fruits of Qingpiguo in Guangxi by the methods of Trizol， improved Trizol， modified guanidine thiocyanate and CTAB， with rich polyphenols and polysaccharide. The results showed that RNA isolated by the improved Trizol showed three clear bands of 28S rRNA， 18S rRNA and 5S rRNA, respectively, and the 28S was about twice in length as 18S， which indicated that little RNA was decomposed and the purity of RNA was very high （D260/D280=201；D260/D230=202）. In addition， the RNA integrity （RIN） and yield rate of RNA extracted by the improved Trizol was 950 and （26000±1947） μg·g-1， respectively. RT\|PCR amplification also showed that the quality of RNA isolated from the improved Trizol can meet the demands of molecular biology experiment.

Key words: Siraitia grosvenorii fruit, total RNA extraction, improved Trizol method