Provided is a portable thermal printing device including: a support plate assembly; a heat insulation plate disposed on the support plate assembly; and a heating plate disposed on the heat insulation plate and including a uniform heating plate body, a covering layer, and a heating element disposed between the uniform heating plate body and the covering layer; and an electrical connection element detachably connected to the heating element via magnetic attraction and configured to connect to an external power source and supply power to the heating element. With such a simple structure, portable thermal printing operations can be achieved.