Abstract: With the continuous improvement in data processing capabilities of aerospace devices and the miniaturization and integration of electronic components, the thermal power density of chips has increased significantly, placing more stringent demands on thermal management systems. An ultra-thin vapor chamber with vapor-liquid channel fabrication method is proposed in this paper. The liquid channel features a wick structure formed by sintering a composite wick of copper wire mesh and bundled woven fiber, with its longitudinal liquid transport performance enhanced by an alkali corrosion process. The vapor cavity and support pillars are created by etching a copper substrate. The final 0.55 mm thick device is assembled through high temperature brazing, working fluid filling, vacuum pumping, degassing, and resistance sealing welding. Thermal performance evaluation of the vapor chambers with different filling ratios demonstrated that the unit with a 50% filling ratio achieved the minimum average thermal resistance, measuring as low as 0.015 cm²·°C/W at 70 W/cm² and 0.127 cm²·°C/W even at a high heat flux of 130 W/cm². These findings confirm the effective heat transfer performance of the vapor chamber and offer useful insights for designing ultra-thin thermal management devices.