The invention discloses a semiconductor-cooling-based shielded cabinet temperature control apparatus and method. The control apparatus comprises a shielded cabinet; and a semiconductor refrigeration module, a direct current power supply module, and a temperature control module are arranged inside the shielded cabinet. The semiconductor refrigeration module is connected to the direct current power supply module by the temperature control module; and the temperature control module controls connection or disconnection between the semiconductor refrigeration module and the direct current power supply module. The semiconductor refrigeration module is formed by a plurality of semiconductor cooling plates; a cold surface of each semiconductor cooling plate faces the inside of the shielded cabinet and a hot surface of each semiconductor cooling plate is in contact with the inner wall the shielded cabinet. According to the invention, on the basis of a semiconductor cooling principle, a shielded cabinet can be cooled well; the operation is simple and effective; and the shielding performance of the shielded cabinet is not affected.