A vapor chamber water-filling section sealing structure. The vapor chamber water-filling section sealing structure includes a main body and a capillary structure. The main body has a first plate body and a second plate body, which are correspondingly mated with each other to together define an airtight chamber and a water-filling section. A flange is disposed along an outer periphery of the main body. The water-filling section has a water-filling notch and a water-filling passage. Two ends of the water-filling passage are respectively connected with the flange and the water-filling notch to communicate with the airtight chamber. A portion of the water-filling passage that is connected with the flange is pressed to have a height equal to the height of the flange or lower than the height of the flange. The capillary structure is disposed in the airtight chamber of the main body.