The invention discloses a fixed-point pressurizing and diffusing method and a fixed-point pressurizing and diffusing structure for kerf grouting and hole sealing. According to the method, gas extraction drilling is conducted based on kerf grouting and hole sealing, pressurizing and swelling airbags are fixed to specific positions of extraction tubes during preparation of hole sealing and are sentto in-hole seam and groove positions, and grouting and hole sealing are conducted. Through airbag pressure adjustment, the airbags are pressurized to swell, radial thrust is provided for in-hole slurry flowing, seam and groove spaces are filled with slurry, and the spreading and infiltrating range of the slurry is widened. Fixed-point pressurization and diffusion are realized in sealed spaces to seal gaps around drill holes. By the method, compacting of the in-hole sealing slurry is benefited, and internal cracks of hole sealing materials are reduced. By the method and the structure, the spreading and infiltrating range of the grouting slurry can be widened effectively, quality of kerf grouting and hole sealing can be improved, gas extraction concentration and extraction rate can be increased, and accordingly, high on-site promotion and application value are realized.