The invention discloses a high-entropy quinary alloy with good high strength and high plasticity matching performance. The chemical formula of the high-entropy quinary alloy is AlaCobCrcFedNie (a-e are molar ratios), wherein 1>=a>=0.5, 1.2>=b>=0.7, 1>=c>=0.4, 1>=d>=0.4, and 2.2>=e>=0.8. Furthermore, a:e is 1:1.2-2.5. Furthermore, a is 0.8, b is 1, c is 0.6, d is 0.7, and e is 1.1-2.0. Furthermore,the chemical formula of the alloy is Al0.8CoCr0.6Fe0.7Ni1.1, Al0.8CoCr0.6Fe0.7Ni1.5, Al0.8CoCr0.6Fe0.7Ni1.8, or Al0.8CoCr0.6Fe0.7Ni2.0. The high-entropy quinary alloy has high strength and high plasticity, and the problem that the strength-plasticity matching performance of a high-entropy alloy in the prior art is poor is solved. The invention further provides a preparation method of the high-entropy quinary alloy with the good high strength and high plasticity matching performance. The preparation method is simple, safe and stable.