The purpose of Bufferless Deflection(BD) router is to minimize buffers which occupies significant area in on-chip-network. Existing routing methods determine routing priority based on either golden time or locality, however their performance are usually unpredictable due to high latency variance of flits. In this paper, we proposed a routing method to alleviate this problem by exploiting multiple priority. To improve Quality-of-Service(QoS) in NoC, the proposed routing method determines priority considering both the number of deflection and routing complexity. Experimental results show the proposed routing method improves not only QoS by reducing latency variance with 22% but also performance of NoC with 8%.