High-quality RNA extracted from the twigs of Casuarina equisetifolia is used as the basis for the study of its gene expression. Five RNA extraction methods, i. e. Trizol method, CTAB method, guanidine thiocyanate method, SDS method and Omega RNA isolation kit, were used to extract total RNA from the twigs of C.equisetifolia. The results showed that RNA was unable to be extracted with Trizol and guanidine thiocyanate methods, and the RNA extracted with CTAB method was degraded; only SDS and Omega RNA isolation kit methods could succeessfully to extract RNA from the twigs of C.equisetifolia, however, the RNA quality didn′t meet the requirement of further experiment. SDS method, the most favourable methods in this study, was improved to get better results, and the major improvement was the addition of steps for removing secondary metabolites. Evaluation experiment indicated that RNA with high quality and yield was obtained from the improved SDS method, and could be used for further study of molecular biology such as RT-PCR.