Abstract: Fir plants contain plenty of polysacchrides and polyphenols.Comparing several standard methods for extracting total RNA from fir plant, a modified method which can eliminate the interferences of polysacchrides and polyphenols in the plant tissues was constructed in the present study. The high-quality RNA sample obtained by the improved CTAB method used to RT-PCR (reverse transcriptase-polymerase chain reaction) of P450 gene study,and the result indicated that the method is easier for operation and is at lower cost.