The utility model discloses an R744 air conditioner pipeline sealing structure. The sealing structure comprises a male connector, an end face sealing gasket, a first O-shaped ring, a second O-shaped ring and a female connector. A sealing shaft of a hollow structure is arranged on the end face of the inner side of the male connector, the sealing shaft is communicated with a connecting hole which isformed in the end face of the outer side of the male connector and used for installing an air conditioner pipe, and the end face sealing gasket, the first O-shaped ring and the second O-shaped ring are sequentially installed on the sealing shaft in the axial direction. A sealing through hole allowing the sealing shaft to be inserted therein is formed in the end face of the inner side of the female connector, is of a stepped structure and communicates with a connecting hole, used for installing an air conditioner pipe, in the end face of the outer side of the female connector. According to theutility model, the requirements of high-temperature and high-pressure impact resistance and strong R744 working medium infiltration capacity required by connection and sealing of components in an R744 air conditioning system can be met, the problem of difficulty in assembly of female and male joints is solved by adopting a double O-shaped ring non-equal-diameter design, and the field assembly efficiency is effectively improved.