The invention provides a liquid high-resistance layer for a zinc oxide piezoresistor. A formula comprises Bi(NO3)3, Co(NO3)2, Mn(NO3)2 and CH3COOLi; a preparation method of the liquid high-resistancelayer comprises the following steps: mixing each raw material in the formula with a solvent; heating and dissolving. An application method of the liquid high-resistance layer coats a side face of a resistance piece with a formula solution. The liquid high-resistance layer of the zinc oxide piezoresistor has the beneficial effects that the formula of the high-resistance layer is adjusted and a technology is controlled, so that a body of the resistance piece is matched with the shrinkage rate of a glaze layer; the side face insulation problem of the resistance piece is solved; meanwhile, the square wave discharge capability of the resistance piece is improved. The original fluctuation of glaze layer thickness, caused by the fact that pre-firing shrinkage rates are different, is reduced; theresistance piece has no cracks and the technology is more stable.