This invention provides a clock and data recovery system, which comprises a plurality of gm cells, control device, resistor and capacitor. The gm cells respectively have an input end and an output end. The control devices are connected to these output ends. According to a time value, the control device controls a part of the plurality of gm cells to form a first gm cell, and the control device controls another part of the plurality of gm cells to form a second gm cell. The resistor is connected between the first gm cell and the second gm cell. The capacitor is connected to the second gm cell. Wherein, the control device controls the ratio of the first gm cell and the second gm cell in accordance with a time-division multiplexed manner.