Abstract: Objective  To establish a simple and effective total RNA extraction method of Mycobacterium tuberculosis.  Methods  Cell wall of Mycobacterium tuberculosis were treated by ultrasonic and glass-bead associated with Trizol method respectively, the total RNA was extracted and the influence of different total RNA extraction methods of Mtb were evaluated through fluorescent quantitative RT-PCR. The negative control is ultrapure water instead of template. Each method were extracted from 3 samples for testing. The final result is the average of 3 specimen.  Results  The Ct and △Rn value of glass-bead group is 20.67 and 0.644, 400 W ultrasonic group is 22.09 and 0.571, 240 W ultrasonic group is 21.86 and 0.503, 160 W ultrasonic group is 25.21 and 0.411, bead absent group is 28.40 and 0.299, negative control is 40.00 and 0.000. Conclusion  The wall-breaking effection of glass-bead method is better than that of ultrasonic method.

Key words: Mycobacterium tuberculosis, RNA, , bacterial, Reverse transcriptase polymerase chain reaction, Cell wall, Bacteriological techniques