A magnetoresistive mixer, for mixing a first frequency signal source input and a second frequency signal source input to obtain a mixing signal, comprising: a spiral coil, a bridge-type magnetoresistive sensor and a magnetic shielding layer, wherein the spiral coil is located between the magnetic shielding layer and the bridge-type magnetoresistive sensor; the bridge-type magnetoresistive sensor comprises two pairs of magnetoresistive sensor units (R3-R6) forming a bridge-type structure, one pair of magnetoresistive sensor units being respectively located in each of two regions (7, 8) above or below the spiral coil; each of the magnetoresistive sensor units comprises N array-type magnetic tunnel junction rows, wherein each array-type magnetic tunnel junction row consists of M magnetic tunnel junctions, M and N are both positive integers, the array-type magnetic tunnel junction rows are connected in series connection, parallel connection, or combination of series connections and parallel connections to form two port structures; the spiral coil being configured to produce a current and a magnetic field such that the current direction and the polarity of the magnetic field component in the direction of the sensing axes of the magnetoresistive sensor units is the same within each respective region and is opposite in one region with respect to the other; wherein the magnetoresistive sensor units have the same resistance response to a magnetic field, and have sensing axes to sense magnetic fields perpendicular to the current direction in the spiral coil in the respective region; the magnetoresistive mixer being configured for a first frequency signal source to be input through the spiral coil to produce a magnetic field signal at the magnetoresistive sensor units having the same frequency for causing resistances of the magnetoresistive sensor units to change, for a second frequency signal source to be input through power source and ground ports of the bridge-type magnetoresistive sensor, causing voltages on two ends of the magnetoresistive sensor units to change, and for a mixing signal to be output through a signal output end of the bridge-type magnetoresistive sensor, with a signal frequency of the output mixing signal that is the sum or the difference of frequencies of the first frequency signal source and the second frequency signal source; and wherein the magnetoresistive sensor units are configured to provide a resistance that varies linearly, within a working range, in response to the magnetic field signal of the first frequency signal and are connected in two half-bridges between power and ground such that the total resistance in each half-bridge is constant with respect to the magnetic field signal. a spiral coil, a bridge-type magnetoresistive sensor and a magnetic shielding layer, wherein the spiral coil is located between the magnetic shielding layer and the bridge-type magnetoresistive sensor; the bridge-type magnetoresistive sensor comprises two pairs of magnetoresistive sensor units (R3-R6) forming a bridge-type structure, one pair of magnetoresistive sensor units being respectively located in each of two regions (7, 8) above or below the spiral coil; each of the magnetoresistive sensor units comprises N array-type magnetic tunnel junction rows, wherein each array-type magnetic tunnel junction row consists of M magnetic tunnel junctions, M and N are both positive integers, the array-type magnetic tunnel junction rows are connected in series connection, parallel connection, or combination of series connections and parallel connections to form two port structures; the spiral coil being configured to produce a current and a magnetic field such that the current direction and the polarity of the magnetic field component in the direction of the sensing axes of the magnetoresistive sensor units is the same within each respective region and is opposite in one region with respect to the other; wherein the magnetoresistive sensor units have the same resistance response to a magnetic field, and have sensing axes to sense magnetic fields perpendicular to the current direction in the spiral coil in the respective region; the magnetoresistive mixer being configured for a first frequency signal source to be input through the spiral coil to produce a magnetic field signal at the magnetoresistive sensor units having the same frequency for causing resistances of the magnetoresistive sensor units to change, for a second frequency signal source to be input through power source and ground ports of the bridge-type magnetoresistive sensor, causing voltages on two ends of the magnetoresistive sensor units to change, and for a mixing signal to be output through a signal output end of the bridge-type magnetoresistive sensor, with a signal frequency of the output mixing signal that is the sum or the difference of frequencies of the first frequency signal source and the second frequency signal source; and wherein the magnetoresistive sensor units are configured to provide a resistance that varies linearly, within a working range, in response to the magnetic field signal of the first frequency signal and are connected in two half-bridges between power and ground such that the total resistance in each half-bridge is constant with respect to the magnetic field signal.