Piezoresistive chip and preparation method thereof, and piezoresistive sensor

The invention discloses a piezoresistive chip, a preparation method thereof and a piezoresistive sensor. The piezoresistive chip comprises a substrate provided with a pressure cavity and a Wheatstone bridge located on the substrate; the Wheatstone bridge comprises a plurality of piezoresistors, and the orthographic projections of the piezoresistors on the plane where the substrate is located are all located in the orthographic projection of the pressure cavity on the plane where the substrate is located; the plurality of piezoresistors at least comprise a first piezoresistor, a second piezoresistor, a third piezoresistor and a fourth piezoresistor which are connected with one another; the piezoresistive chip further comprises a shielding layer, the orthographic projection of the shielding layer on the plane where the substrate is located is at least partially overlapped with the orthographic projection of at least one piezoresistor on the plane where the substrate is located, the shielding layer is configured to be connected with a grounding end, and the long-term stability of the piezoresistive chip can be improved.