A minimum delay routing（ MDR） protocol is proposed to meet the requirement of delay for event-driven wireless sensor networks. It uses RTS / CTS information mechanism to set up routing

the data packet of a node to sink

compared with other routing algorithm

it significantly decreases the computational overhead. On this basis

sensor-to-sink delay is minimized by controlling the number of subregion of forwarding destination area of node and its backoff window time span. Experimental results show that the proposed protocol outperforms the traditional routing protocol in terms of the end-to-end delay.