Storage battery is the integrant back power supply in the communication system, and its using life and security reliability are specially concerned by users. To avoid the accidents induced by the individual battery failure in the long-term using process, the running status of the storage battery must be maintained and monitored periodically. A new and advanced capacity measurement technology, i.e. the whole-online discharge monitoring technology is proposed in this article. Comparing with other discharge technologies, it could utilize the existing real loads and the locale power cut to complete the data acquisition of the storage battery without any adjustment and special power cut, and it has no any risk to realize the online monitoring and in-time failure diagnose to the storage battery, and it could not only simplify the battery discharge maintenance operation, but enhance the working efficiency of the maintenance.