An all-digital intelligent temperature and humidity control dehumidification system is arranged in a housing of a cabinet of an electrical device and comprises a heater, a dehumidifier, a controller which is connected with and control the heater and the dehumidifier, and a temperature and humidity sensor communicated with the controller. According to the all-digital intelligent temperature and humidity control dehumidification system, the temperature and humidity sensor is used for continuously measuring the change of relative humidity and temperature in the cabinet, the controller is used for automatically controlling the start and stop of the dehumidifier and the heater, and the heater is started for working in matching when the temperature is low, so that the system can work at a wide temperature range stably, the air humidity in the cabinet can be ensured to be maintained at a reasonable range, the humidity in the cabinet of the electrical device can be effectively reduced, the condensation in the cabinet of the electrical device can be effectively eliminated, all kinds of accidents caused by damp can be prevented, and the energy efficiency is obtained; meanwhile, the dehumidifier serves as the core, the heater and the ventilation design are used for auxiliary dehumidification, and self-test and protection functions are arranged, so that the safety of the operation of the device can be effectively improved.