A new concept of μ-cell fatigue test is proposed. By reciprocating a cell across the throat of a micro channel repeatedly, the dynamic deformation behavior of the cell is measured. We define a new index of fatigue characteristics of cells as the number of reciprocatory motion leading to a prescribed recovery ratio. The test system is composed of a piezoelectric (PZT) actuator, a high speed vision sensor and a micro channel with a throat. Preliminary experiments were conducted by using Red Blood Cells (RBCs). The result suggested that the activation level of a cell can be evaluated based on its fatigue characteristics.