Rod-like Co₃(HITP)₂ microstructures are synthesized via a solvothermal method. By introducing reduced graphene oxide (rGO) during the synthesis, rGO/Co₃(HITP)₂ composites with different rGO content (1 g/L, 1, 10 and 100μL) are prepared. The influences of rGO on the morphology, structure, and room-temperature gas-sensing properties of Co₃(HITP)₂ are systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and gas-sensing analysis. The results indicate that the addition of rGO affects the formation of the rod-like Co₃(HITP)₂ structure, causing slight changes in the structural and morphology. Furthermore, the amount of rGO also affects the sensing property. Among all sensors, rGO₁₀/Co₃(HITP)₂ sensor demonstrates optimal gas-sensing performance, exhibiting a response value of 4.3 toward 2×10^–5 (volume fraction) H₂S at room temperature (~25℃) and 25% relative humidity (RH), with a detection limit of 5×10^–8 (volume fraction). Furthermore, the rGO₁₀/Co₃(HITP)₂ sensor shows excellent selectivity, strong anti-interference ability, and fast response/recovery characteristics (92 s/256 s). Band structure analysis reveals that the synergistic effect between rGO and Co₃(HITP)₂ is the mainly responsible for the enhanced gas-sensing properties of the composite. Despite its significant sensitivity to humidity, the rGO₁₀/Co₃(HITP)₂ sensor demonstrates superior performance at room-temperature compared with that at higher temperatures. This work provides important guidance for achieving the efficient room-temperature detection of H₂S gas.