The invention relates to a heating brick of a plastic-adsorption machine, which is characterized in that: a structure form of electro-magnetic induction heating is adopted, comprising a solenoid coil which takes high-frequency power supply as working power supply and is used for generating high-frequency alternating magnetic field, and a heating plate which is arranged in the high-frequency alternating magnetic field generated by the solenoid coil and generates heat by the electro-magnetic induction; aiming at the specific application of the heating brick in the plastic-adsorption machine, the heating part is heated by eddy current by utilizing the electro-magnetic induction principle, the heating mode is directional, so as to effectively inhibit the non-effective heat radiation to the circumferential space, and the heating efficiency of the heating brick is improved by more than 20 percent compared with the resistance-type heating brick of the plastic-adsorption machine.