A cell activation reactor and a cell activation method are provided. The cell activation reactor includes a body, a rotating part, an upper cover, a microporous film, and multiple baffles. The body has an accommodating space, which is suitable for accommodating multiple cells and multiple magnetic beads. The rotating part is disposed in the accommodating space and includes multiple impellers. The microporous film is disposed in the accommodating space and covers multiple holes of the accommodating space. The baffles are disposed in the body. When the rotating part is driven to rotate, the interaction between the baffles and the impellers separates the cells and the magnetic beads.