Abstract: For studying the simulated microgravity in rotating bioreactor and the movement of micro-carrier in the microgravity fluid, two methods were applied to verify the effect of simulated microgravity in rotating bioreactor:keeping the effective acceleration of gravity far less than the surface gravity acceleration, or the " approximate static" condition for micro-carrier in the aqueous solution.In the self-developed perfusion system in rotating bioreactor, the motion displacement and speed of micro-carrier were analyzed to find out the movement rules of micro-carrier in the aqueous solution, and the ideal radius of membrane oxygenator in cell bottle was decided by centrifugal force calculating.The results showed that micro-carrier moved from center to outside following a certain rule until touching the wall.To get better test results, the radius of membrane oxygenator was set to be a small parameter between 0.3 733-0.8 042 cm.