Abstract: The monitoring/alarming system is developed for protecting the unattended valve chamber, by the way of remotemonitoring and real-time alarming. With the combination of the door-sensor and dual-technology detector, this system canrealize the protection of the valve chamber by detecting the invasion and the movement of the object in the valve chamber.Inflammable gas detector is used to detect the leakage of substances in the pipeline. When invasion or leakage happens, thesystem will remind the staff to keep away with an audible and visual alarm, and actively take a photograph of the onsiteimage and send it to the remote control center with the mobile phone network. The remote control center can perform areal-time monitoring and make a judgment of the performance of the valve chamber. The onsite application shows that thesystem has the advantages of high reliability, in-time alarm, and low false-alarm rate, which can meet the requirements ofthe protection of the valve chamber.