The invention provides a device and method for vacuum attaching of the spherical surface of a metal spherical shell and the concave spherical surface of a metal body. The device comprises a communicating pipe, a one-way valve sealer and a one-way valve. One end of the communicating pipe is communicated with a closed gap between the spherical surface of the metal spherical shell and the concave spherical surface of the metal body, and the other end of the communicating pipe is communicated with the one-way valve. The one-way valve is arranged in the one-way valve sealer, and the one-way valve sealer is used for landfilling and plugging the one-way valve. The method has the advantages that the spherical surface of the metal spherical shell is permanently and tightly attached to the concave spherical surface on the metal body; the concave spherical surface of the metal spherical shell is smooth and free of damage; the device is simple and extremely low in cost; and the method is simple and convenient and easy to operate.