Abstract: Objective: Studying the effect and mechanism of MT on erythrocyte deformability in morphine dependent rats. Methods: After 5 days, a model of morphine dependent rats was established by gradually increasing the doses of morphine subcutaneous injection for rats. MT test group rats was injected with MT（50mg/kg） by peritoneoscope, Meanwhile, Then rats were injected with naloxone （0.5mg/kg）.ED was detected to observe the changes of ED of rats. Results: ED of morphine dependent rats was lower than that of the normal control. MT could obviously inhibit the above change. Moreover, if morphine, NE, cAMP of different doses were directly added into blood of normal rats,it could reduce the ED clearly; But MT could have an betterment to the change in a dose dependent manner. Conclusion: MT may obviously improve the decreasing of ED in morphine dependent rats. It may be resulted by protecting RBC directly or inhibiting the hyperfunction of the sympathetic system and protein G-cAMP system.