Delay Tolerant Mobile Sensor Network (DTMSN) is the network for pervasive information gathering. Traditional static routing approaches may not fit for DTMSN due to its intermittent connectivity. This paper proposes a Relative Distance Based Routing (RDBR) strategy for DTMSN, in which nodes delivery probabilities are calculated and updated according to the latest relative distance from them to the sink node, and data are delivered according to nodes' delivery probabilities. RDBR also introduces a redundant copies controlling technique based on the message priority. Simulation results show that RDBR achieves a well tradeoff between the data delivery ratio/delay and the delivery overhead.