Rhenium (Re)-based transition metal dichalcogenides (TMDs) have excellent in-plane anisotropic optical and electrical properties. However, their distorted octahedral (1T') structure and weak interlayer coupling easily lead to anisotropic and out-of-plane growth, which makes it particularly difficult to prepare large-area Re-based TMD continuous porous films on SiO/Si substrates. In this work, ReS films are synthesized on SiO/Si substrates by using tellurium (Te) powder-assisted chemical vapor deposition, and then the films are selenized to synthesize a series of continuous large-area ReSSe ( = 0, 0.34, 0.56, 0.84, and 0.91) nanosheet-formed porous films. Furthermore, prototype ReSSe photodetectors with different Se compositions are fabricated. The surface morphology, high quality crystallization and compositions are confirmed by various characterization techniques. The ReSSe photodetectors based on these films show excellent ultraviolet-visible (UV-vis) spectral responses and self-powered characteristics. The response time is faster, and the photocurrent increases with the Se composition. Due to the Schottky barrier generated by the Ag-ReSSe interface, the device without bias voltage has a superior responsivity (121.9 mA W), high detectivity (5.27 × 10 Jones), good on/off ratio (1.2 × 10) and fast response time (rising/decay times, 30/60 ms) under 365 nm light irradiation. This simple and controllable method opens up a new way to produce high-quality vertically oriented ReSSe porous arrays on SiO/Si substrates for next-generation application in UV-vis photodetectors.