The invention discloses a high-strength and high-toughness weldable corrosion-resistant and abrasion-resistant steel plate and a preparation method thereof. According to the technical scheme, the steel plate comprises, by mass, 0.25-0.42% of C, 0.01-0.10% of Si, 1.35-1.75% of Mn, not greater than 0.005% of P, not greater than 0.002% of S, 0.35-0.55% of Mo, 0.07-0.19% of Ti, 0.12-0.25% of Zr, 0.0023-0.0045% of Mg, 0.015-0.025% of Als, 0.001-0.008% of B, 0.0025-0.0040% of N, 0.0005-0.0015% of O, and the balance Fe and trace impurity elements, wherein the ratio of Mo to Ti is 1.8-7.0, and the ratio of Ti to Als is 3-13. According to the high-strength and high-toughness weldable corrosion-resistant and abrasion-resistant steel plate and the preparation method thereof, the alloy adding amount is small, the welding performance is improved, and the production cost is reduced; and through whole-process technological control of rolling, online quenching, offline quenching and low-temperature tempering, the grain size is refined, precipitation and dispersion distribution of nanoscale Ti-containing second-phase particles are promoted, and the toughness and corrosion-resistant and abrasion-resistant performance of the product are improved.