Abstract: The present application provides an Uvaria grandiflora extract as a botanical fungicide, a preparation method therefor, and an application thereof. The broad-spectrum plant-derived fungicide provided in the present application comprises: Uvaria grandiflora whole plant extract and compound zeylenone obtained through separation and purification, which have the advantages of a broad antibacterial spectrum and a simple separation process. By means of a potted fungicidal activity test, it is proven that Uvaria grandiflora extracts have excellent control effects on Phytophthora capsici, cucumber downy mildew, potato late blight, and cowpea powdery mildew. Furthermore, Uvaria grandiflora extracts promote cucumber growth. Furthermore, a field efficacy test proves that the fungicidal activity of Uvaria grandiflora extracts against cucumber powdery mildew is better than that of the commercial fungicide Luna Sensation.