A novel heterostructured ZnO/ZnS ring structure has been synthesized. The formation process of the ring is attributed to the strain induced bending that arises mainly from the lattice mismatch between ZnO and ZnS. This growth model is in consistent to the electrostatic model proposed previously about the formation of nanorings, nanosprings and nanohelices, but it shows the dominant contribution from interface strain in the ring formation for such a special case. The ring structure of ZnO/ZnS provides an ideal candidate for investigate optoelectronics of ring structured II-VI semiconductors.