The invention discloses a preparation method of a high-gradient zinc oxide piezoresistor high-resistance layer with the high through-flow capacity. According to the method, a blank body and the high-resistance layer are included. The high-resistance layer wraps the blank body. The high-resistance layer is prepared from ZnO, Fe2O3, Bi2O3, Sb2O3, SiO2, MnO2, Li2CO3 and Ni2O3. The blank body is the zinc oxide piezoresistor blank body and is prepared from ZnO, Fe2O3, Bi2O3, Sb2O3, SiO2, MnO2, Li2CO3 and Ni2O3. The method has the advantages that the mechanical strength of a piezoresistor is improved, the phenomena of cracking and flashover are avoided, the dielectric strength of the side face of the piezoresistor body can be improved, and the through-flow area of the body is not affected.