Semiconducting heterostructures with type-II band structure have aroused much attention due to their novel physical properties and wide applications in optoelectronics. Herein, we report, for the first time, a controlled synthesis of type-II ZnS/SnO2 heterostructured ribbon composed of SnO2 nanoparticles that conformally cover on the surface of ZnS ribbon via a simple and versatile thermal evaporation approach. Structural analysis indicated that majority of SnO2 nanoparticles have an equivalent zone axis, i.e., <-313> of rutile SnO2, which is perpendicular to ±(2-1-10) facets (top/down surfaces) of ZnS ribbon. For those SnO2 decorated on ±(01-10) facets (side surfaces) of ZnS ribbon, an epitaxial relationship of (01-10)ZnO//(020)SnO2 and [2-1-10]ZnO//[001]SnO2 was identified. To explore their electronic and optoelectronic properties, we constructed field-effect-transistors (FETs) from as-prepared new heterostructures, which exhibited an n-type characteristic with an on/off ratio of ~103 and a fast carrier mobility of ~33.2 cm2V-1s-1. Owing to the spatial separation of photogenerated electron-hole pairs from type-II band alignment together with the good contacts between electrodes and ribbon, the resultant photodetector showed excellent photoresponse properties, including large photocurrent, high sensitivity (external quantum efficiency as high as ~2.4×107%), good stability and reproducibility, and relatively fast response speed, respectively. Our results suggest great potential of ZnS/SnO2 heterostructures for efficient UV light sensing, and more importantly, signify the advantages of type-II semiconducting heterostructures for construction of high performance nano-photodetectors.