Querying the path information of individual products in a supply chain is key to many applications. RFID (RadioFrequency IDentification) is a main technology to enable product path information query today. With RFID technology, supply chain participants can efficiently track products in transit and record their states in databases. In this paper, we investigate the following question: how can we conduct privacy-preserving product path information query with verifiability on an RFIDenabled distributed supply chain? We address this question with Double Edged(DE)-Sword, an incentivized verifiable query system. DE-Sword introduces a novel double-edged reputation incentive mechanism to encourage supply chain participants to behave; and couples it with cryptographic primitives and careful protocol design. We evaluate DE-Sword through security analysis and performance experiments. The security analysis shows that DE-Sword guarantees both verifiability and privacy. The experiment results show that DE-Sword achieves low overhead in RFID-enabled supply chain applications.