Excessive temperatures can significantly impair the service life and performance of electronic devices, making the cooling of such devices an increasingly critical issue. This Communication introduces for the first time a three-dimensional hydrogel designed for effective thermal management. The heat from the gateway equipment is absorbed through the desorption of water molecules within the composite hygroscopic material (SHM) encapsulated in the gel, leading to a remarkable cooling effect. Additionally, the material's spontaneous adsorption capability enables self-recovery. Under conditions of 80% relative humidity and at a voltage of 5.5 V, 0.35 g of hygroscopic material (with a 5% content) has demonstrated a significant cooling effect, achieving a temperature reduction of up to 11.5 °C. This represents a substantial advancement compared to traditional phase change materials (PCM). The approach holds broad application prospects for the future.