The invention relates to a door controller with a safety relay. The door controller comprises a safety relay activation logic circuit, a safety relay deactivation logic circuit, an RS (Relay Selector) latch and the safety relay, wherein a normally-opened contact of the safety relay is connected with an unlocking circuit of the door controller in series; when all inputted train signals simultaneously meet door opening conditions, the safety relay activation logic circuit outputs an effective activation signal to the S end of the RS latch; when the inputted train signals show normal closing and no effective door opening instruction, the safety relay deactivation logic circuit outputs an effective deactivation signal to the R end of the RS latch; the RS latch controls the activation and the deactivation of the safety relay. The door controller disclosed by the invention has the beneficial effects that the safety relay is added in the door controller; a train door is always kept closed during operation by a self-locking mode; meanwhile, the train door can be opened under the condition that accurate signals are found, so that the safety and the stability of the door control system are improved.