Dendrite-like ZnO@Ag heterostructure nanocrystals are designed and fabricated by a facial two-step chemical method in a large scale. The heterostructure nanocrystals are composed of single crystal Ag nanowires as trunks and highly dense (0001) oriented ZnO nanorods as branches. ZnO nanorods with diameters of about 50−400 nm are vertically grown on the six lateral surfaces of the Ag nanowires. Ultrathin ZnO nanowires or nanotubes with a diameter of less than 30 nm are decorated on the ZnO nanorods. The photocatalysis test shows that the ZnO@Ag heterostructures exhibit a higher photocatalytic activity than the pure ZnO nanorods, thereby implying that the Ag/ZnO interfaces promote the separation of photogenerated electron−hole pairs and enhance the photocatalytic activity.