By comparing and analyzing the current anti-condensation methods for the outdoor terminal boxes of substations,a design scheme for the detachable anti-condensation device of such terminal boxes and the corresponding intelligent control system suitable for engineering sites is proposed to achieve the optimization of anti-condensation effects and economic costs.The application in the substations shows that the detachable anti-condensation devices of terminal boxes and the designed intelligent control system present good anti-condensation effects,stable operation and meeting the expected design requirements.