A vapor chamber manufacturing method, comprises steps of material preparation, powder filling and sintering, pre-punching, supporting structure infilling, the first pressing, the first sealing, fluid injection, and vacuum processing; a sealing structure comprises a semi-finished vapor chamber with a vacuum cavity, a fluid injection port positioned on one side of the vapor chamber, and a supporting structure filled in the vacuum cavity and supporting the shape of the vapor chamber, wherein the fluid injection port is formed of one portion of one side of the vapor chamber by pressing and sealing, no fine metal pipe as fluid injection port is required herein; after the step of fluid injection, an integrated step of vacuum pumping, pressing and sealing is conducted within a vacuum chamber, to provide the product with higher performance and lower rejection rate.