The invention discloses a bioreactor, a stirring paddle thereof, and a method using the bioreactor to culture CIK cells. The stirring paddle is wrapped by a material capable of reducing the shearing force. The bioreactor is provided with the stirring paddle wrapped by a material capable of reducing the shearing force and is used to culture CIK cells. The bioreactor is used to culture CIK cells, the stirring paddle is wrapped by a material capable of reducing the shearing force, thus damage of shearing force on cells is reduced, and massive amplification of cells is promoted therefore. The stirring is nonstop during the culture process, the culture system is dynamic, the gas exchange for cells is promoted, uniform culture environment is provided for cells, and thus the massive amplification of cells is promoted. The provided method has the advantages that a large amount of CIK cells is massively amplified, moreover, the expression amount of surface antigen of obtained CIK cells is high, and thus the killing activity on tumor cells is stronger.