RFID and cloud computing technologies have been widely applied in warehouses to improve the efficiency and accuracy of inventory management based on the above excellent features. Besides the detection of missing RFID tags, a number of efficient schemes are proposed in recent studies, in which the security and privacy aspects are less concerned. In real-world applications, the integrity of tag data is an important factor. To address these problems, we propose an inventory data integrity detection scheme for cloud-based Internet of things warehouse systems. For the purpose of evaluation, we conduct experiments to compare the proposed detection protocol and tag data update protocols with existing schemes in simulations. The results show that the proposed scheme has better performance, as it not only identifies the missing tags in a secure and efficient way but also enables dynamic tag data integrity management quickly.