Abstract: The study aims to investigate the preservation methods of cassava germplasm in vitro. The authors used cassava tissue culture plantlets as the main material to observe the survival rate of transplanting plantlets in green house, the growth change of plant height and stem in test tube, and to compare the effect of cassava germplasm preservation in different tissue culture medium. Results showed that, in the culture room of temperature (25±2)℃, light intensity 3000 lx and photoperiod 16 h/8 h, cassava germplasm tissue culture plantlets in medium with pH 5.8 and MS 0.2 mg/L NAA 80 mg/L Kan 30 g/L sucrose 9 g/L agar could well survive for 22 to 24 months, the survival rate of transplanting plantlets in green house was more than 90%, 5-8 times of the survival rate in normal medium without any kanamycin. The study developed a good method to preserve cassava germplasm in vitro for remarkable cost saving of labor, reagents, water and electricity energy. It could also provide good quality of tissue culture plantlets for further utilization.