A loading and unloading mechanism adopted for use on removable power supply modules includes in one embodiment a connection plug installed on a removable power supply and a connection trough connected to a power supply circuit of a system end (such as a personal computer). Another embodiment includes a connection trough on a system end to be installed on a holding unit which is movable to adjust the position relative to the system end according to the size of the removable power supply so that the removable power supply can be fully loaded into the computer. The loading and unloading mechanism thus formed can be adapted for the removable power supply of varying sizes and specifications.