Layered chalcogenides have been considered as excellent candidates for superconductor and thermoelectricity applications. The pressure-driven 2D–3D structural reconstruction is an efficient strategy for tuning the electronic configuration and optical properties. With aids of in situ structural, optical and electronic characterizations, we uncovered the giant enhancements in the electronic transport and phototelectric properties with the pressure tuning effect on this layered materials. Comparing the pressure induced structure phase transition in many 3D materials, the pressure-driven buckling effect on the layered bismuth oxysulfide Bi9O7.5S6 is significent. Under pressure, the layer and bonding distances between and within BiO and BiS layer change dramatically, which drives the enhancements of electric conductivity by 6 orders of magnitude, increasing of photocurrent by 4 orders of magnitude, and significant narrowing down of band gap from 1.34 to 0.45 eV. These findings may open up a new avenue for discovering and designing high-efficiency photodetectors and energy-harvesting materials.