The invention relates to a method and a device for monitoring an unlocked key management box based on special optical fiber communication telecontrol. The method comprises the following steps: monitoring a box door and a key of the unlocked key management box by virtue of a power telecontrol channel; transmitting the information state to a dispatching desk host if an unlocked key is needed on the site and a specific responsibility or same permission people are absent on the site; receiving the information state and verifying remote unlocking by virtue of a dispatching telephone; monitoring whether the unlocked key is returned or not by virtue of infrared detection if unlocking is performed; finishing the unlocking if the unlocked key is returned; and forcing the locked box door to lock if the unlocked key is not returned. According to the method disclosed by the invention, special acquisition control and telecontrol communication resources of the power grid are fully utilized, the unlocked key management box is safely and efficiently monitored by virtue of special optical fiber communication telecontrol of the power system, the key box door is taken away and cannot be locked, the condition that the door is locked by accident is avoided, and the key use can be supervised. The invention also discloses a device for monitoring the unlocked key management box based on special optical fiber communication telecontrol.