Abstract: In vitro conservation by growth retardation of Phalaenopsis amabilis shoots and genetic stability of the regenerated plantlets were studied.The results showed that, at (24±3) ℃ with a 12 hphotoperiod of 2 000-2 500 lx in the initial 3 months followed by 500-1 000 lx for another 3 months, 96.3% of the shoots could be satisfactorily preserved in vitro for 18 months on the medium containing Hyponex No.1 3.0g·L-1+AC 0.5g·L-1 supplemented with 10g·L-1 sucrose.When the medium, Hyponex No.1 3.0g·L-1+AC 0.5g·L-1+sucrose 20g·L-1 supplemented with 15g·L-1 mannitol or 6.0mg L-1 PP333, was applied, the survival rate was80.0%for 18 months, but a high proliferation rate of 4.1 was obtained.After the treatments, all plantlets recovered normal growth with no significant morphological deviations from the control.The RAPD analysis also exhibited no different bands from the control, indicating agenetic stability of P.amabilis toward the treatments.