A Y-axis magnetoresistive magnetic field sensor, comprising a substrate, and a first comb-shaped soft ferromagnetic flux guide, a second comb-shaped soft ferromagnetic flux guide, and a push-pull magnetoresistive bridge sensing unit located on the substrate; wherein first comb teeth and a first comb base of the first comb-shaped soft ferromagnetic flux guide and second comb teeth and a second comb base of the second comb-shaped soft ferromagnetic flux guide are all rectangular, major axes and minor axes of the first comb teeth and the second comb teeth are parallel to the Y axis and the X axis, respectively, and major axes and minor axes of the first comb base and the second comb base are parallel to the X axis and the Y axis, respectively; the first comb-shaped soft ferromagnetic flux guide and the second comb-shaped soft ferromagnetic flux guide are formed into an interdigitated structure, first and second gaps are alternately formed in sequence between the first comb teeth and the second comb teeth which are adjacent, and third and fourth gaps (10, 11) are respectively formed between the second comb teeth and the first comb base as well as between the first comb teeth and the second comb base; and the push-pull magnetoresistive bridge sensing unit comprises push and pull magnetoresistive sensing unit strings, each of the push and pull magnetoresistive sensing unit strings comprises multiple magnetoresistive sensing units connected in series and/or connected in parallel, the push and pull magnetoresistive sensing units are parallel to the Y-axis, and respectively extend along the first and second gaps, the push and pull magnetoresistive sensing unit strings are electrically connected to form a push arm and a pull arm, respectively, the push arm and the pull arm comprise the same number of the magnetoresistive sensing unit strings, the push arm and the pull arm are electrically connected to form the push-pull magnetoresistive bridge sensing unit, and the magnetoresistive sensing units sense the magnetic field along the X-axis. a substrate, and a first comb-shaped soft ferromagnetic flux guide, a second comb-shaped soft ferromagnetic flux guide, and a push-pull magnetoresistive bridge sensing unit located on the substrate; wherein first comb teeth and a first comb base of the first comb-shaped soft ferromagnetic flux guide and second comb teeth and a second comb base of the second comb-shaped soft ferromagnetic flux guide are all rectangular, major axes and minor axes of the first comb teeth and the second comb teeth are parallel to the Y axis and the X axis, respectively, and major axes and minor axes of the first comb base and the second comb base are parallel to the X axis and the Y axis, respectively; the first comb-shaped soft ferromagnetic flux guide and the second comb-shaped soft ferromagnetic flux guide are formed into an interdigitated structure, first and second gaps are alternately formed in sequence between the first comb teeth and the second comb teeth which are adjacent, and third and fourth gaps (10, 11) are respectively formed between the second comb teeth and the first comb base as well as between the first comb teeth and the second comb base; and the push-pull magnetoresistive bridge sensing unit comprises push and pull magnetoresistive sensing unit strings, each of the push and pull magnetoresistive sensing unit strings comprises multiple magnetoresistive sensing units connected in series and/or connected in parallel, the push and pull magnetoresistive sensing units are parallel to the Y-axis, and respectively extend along the first and second gaps, the push and pull magnetoresistive sensing unit strings are electrically connected to form a push arm and a pull arm, respectively, the push arm and the pull arm comprise the same number of the magnetoresistive sensing unit strings, the push arm and the pull arm are electrically connected to form the push-pull magnetoresistive bridge sensing unit, and the magnetoresistive sensing units sense the magnetic field along the X-axis.