A direct-current fan control chip comprises a magnetoresistive sensor (4), a controller (5), a driver (6) and a substrate (7). The magnetoresistive sensor (4), the controller (5) and the driver (6) are integrated on the substrate (7). The sensing direction of the magnetoresistive sensor (4) is perpendicular to or parallel to the surface of the direct-current fan control chip. The magnetoresistive sensor (4) provides the controller (5) with a rotor position signal, a rotor speed signal, and rotor a rotation direction signal for the controller. The controller (5) outputs a control signal to the driver (6) according to the received signals. After receiving the control signals, the driver (6) outputs a drive signal. This control chip has the advantages of good temperature stability, good frequency response and so on.