Abstract: Embodiments of the present invention relate to the field of soldering sheets, and provided therein are an ultra-thin soldering gasket and a preparation method therefor, a soldering method, and a semiconductor device. The ultra-thin soldering gasket comprises: an internal support structure and a solder layer which covers a surface of the internal support structure, the solder layer being formed by uniformly attaching a solder liquid to the surface of the internal support structure. The preparation method for an ultra-thin soldering gasket comprises the following steps: immersing an internal support structure that has passed through a surface treatment process into a solder liquid, then removing same, and cooling. The soldering method based on the ultra-thin soldering gasket comprises: placing an ultra-thin soldering gasket between soldering surfaces to be soldered, and then performing reflux soldering to form a semiconductor device.