The present disclosure provides a method for preparing a piezoresistive sensor material, including: preparing a wood fiber aerogel; conducting dopamine self-polymerization on the surface of the aerogel to obtain a wood fiber-based hydrogel; soaking the wood fiber-based hydrogel in a nano conductive phase suspension or a nano conductive phase precursor to form a conductive phase-loaded wood fiber-based hydrogel; subjecting the conductive phase-loaded wood fiber-based hydrogel to reaction with an aqueous solution including a polyelectrolyte monomer, a crosslinker, an initiator and a catalyst to form a conductive phase-wood fiber-based hydrogel composite; and complexing the composite with metal ions. The present disclosure further discloses a piezoresistive sensor including the sensor material, and a preparation method thereof. The sensor material prepared by the method of the present disclosure has excellent mechanical strength and ionic conductivity, and a sensor further prepared has extremely-high sensitivity.