The present invention provides a low-alloy high-performance wear-resistant steel plate and a manufacturing method thereof. The steel plate comprises the following chemical compositions (wt%) of 0.21-0.32% of C, 0.10-0.50% of Si, 0.60-1.60% of Mn, 0.0005-0.0040% of B, 0-1.50% of Cr, 0-0.80% of Mo, 0-1.50% of Ni, 0-0.080% of Nb, 0-0.080% of V, 0-0.060% of Ti, 0.010-0.080% of Al, 0.0010-0.0080% of Ca, 0-0.0080% of N, 0-0.0080% of O, 0-0.0004% of H, 0-0.015% of P, and 0-0.010% of S, wherein the following relationships are satisfied: 0.20%<=(Cr/5+Mn/6+50B)<=0.55%, 0.02%<=(Mo/3+Ni/5+2Nb)<=0.45%, 0.01%<=(Al+Ti)<=0.13%, and the balance is Fe and inevitable impurities. The low-alloy high-performance wear-resistant steel plate manufactured by the above compositions and through a TMCP process has high strength and hardness, good toughness and excellent wear resistance, and is suitable for easy-to-wear parts in various mechanical equipments.