Abstract: CO2 supercritical fluid drying technique was proposed on Trema （Trema orientalis） to study the effect of drying technology on wood dimensional stability. the results showed that wood treated by CO2 supercritical fluid drying could basically maintain the original dimension and figure, without deformation, discoloration and crack. On the test, the sequence of every factor for wood from high to low was supercritical temperature, supercritical drying time and supercritical pressure. The influence of supercritical temperature was significant. The change rate of the terminal area was reduced as the temperature increasing. For Trema wood drying, the optimal drying technology were the the following combination: supercritical temperature 60℃, supercritical pressure 12MPa and supercritical dying time 3h.