The invention discloses a natural gas diffusion coefficient measurement auxiliary device based on a hand-operated lifting device, comprising a core chamber, a bracket, a core preservation device, and a hand-operated lifting device; the left side of the core chamber is connected with a methane measuring chamber, and the right side of the core chamber is connected with a nitrogen measuring chamber; a rotatable bracket is installed on the lower left side of the core chamber, and the lower right side of the core chamber is connected with the hand-operated lifting device; the core chamber is rotated by the hand-operated lifting device with the support as the center; a horizontal platform at the lower part of the core chamber is provided with a revolving door that can accommodate the left end of the core chamber; a core preservation device is installed at the lower part of the revolving door. The invention has a simple structure, which greatly reduces the time required to load the core during natural gas diffusion coefficient measurement, and can effectively prevent the core from breaking and the rubber sleeve from being damaged.