A fungicidal composition is provided. The effective ingredients of the composition comprise active components A and B, wherein the active component A is a compound having a structure of Formula (I), and the active component B is mancozeb; and the weight ratio of the two components is 1:1-400. Also provided are a preparation method and use of the composition. Test results show that the fungicidal composition has an obvious synergistic effect, and more importantly, the application rate is reduced and the cost is lowered. The fungicidal composition is effective in controlling certain specific fungal diseases of the crops. Through the combination of different fungicides with different mechanisms and modes of action, the application rate of each single agent is effectively reduced, and a good effect on broadening the fungicidal spectrum, retarding the development of fungal resistance and improving the control effect is exhibited.