With the rapid development of high-power electronic devices, phase change heat transfer has attracted much attention for efficient and lightweight thermal management. However, the mesh structure design for aluminum-based pool boiling enhancement still lacks experimental investigation and theoretical analysis. Herein, an aluminum gradient mesh wick is developed for efficient heat transfer performance. The optimized gradient mesh wick is comprised of a large-hole rhombus flat punching structure on the top and a small-hole 2D screen woven mesh on the bottom, providing sufficient active nucleation density sites, timely liquid supply, and rapid bubble departure. The gradient mesh design for pool boiling enables to achieve a high critical heat flux (CHF) of 1095.46 kW/m2 and a high heat transfer coefficient (HTC) of 46.20 kW/m2·K at a wall superheat of 23.70 °C, which is 167.06% and 240% that of Al plate, respectively. The visualization of bubble behaviors and theoretical analysis reveals that the CHF of the gradient mesh wick mainly depends on the bubble departure and liquid supply, and the bubble departure accounts for a greater proportion. Such aluminum gradient mesh wick provides a strategy for efficient thermal management of lightweight and high-power electronic devices. •An aluminum gradient mesh wick for pool boiling enhancement is proposed.•A high CHF and HTC of 1095.46 kW/m2 and 46.20 kW/m2·K at a wall superheat of 23.70 °C are achieved.•The visualization of bubble behavior and theoretical analysis are proposed for the mechanistic explanation of pool boiling.