The invention provides an electromagnetic brake mechanism of an electric tricycle. The problems of brake part replacement and complicated maintenance procedures due to structural limitation in the prior art are solved. The electromagnetic brake mechanism comprises a connecting drive shell, a limiting shell and a first limiting block, wherein the connecting drive shell is arranged on a vehicle frame on the inner side of a rear wheel; the limiting shell is arranged in the connecting drive shell and is provided with a travel path group; and the first limiting block is slidably connected with thelimiting shell and moves along the travel path group. The electromagnetic brake mechanism of the electric tricycle has a simple structure, and the maintenance or replacement of the first limiting block can be carried out only after the connecting drive shell is removed, thus the overall operability is improved, and the overall operation difficulty is reduced.