This paper proposes CET, a community based event transmitting protocol in publish/subscribe system for Delay Tolerant Sensor Networks (DTSN). The core idea of CET is that event transmitting is based on communities which are formed by sensors in the network according to their connectivity. CET consists of two key components data transmission and queue management. In data transmitting, not only events are transmitted to mobile subscribers as best as possible, some events in subscribers are also retransmitted to sensors in community, for enhancing the data delivery ratio. The queue management employs both the event survival time and the successful delivery time to decide whether the event should be transmitted or dropped for minimizing the transmission overhead. Simulation results have shown that the proposed CET achieves a higher event delivery ratio with the lower transmission overhead and event delivery delay than DG (direct gathering protocol).