Chameleon authentication tree (CAT) is an important authenticated data structure for verifiable data streaming in 5G networks. But the typical CAT cannot support the dynamic scenario very well because it cannot expend freely since its height is fixed. Therefore, we proposed a dynamic CAT (DCAT) with the feature of adaptive expansion. We divided the algorithms of the DCAT with the following phases: setup, append, query, and verification. The DCAT removes the drawbacks of the static CAT. In the setup phase, it is not required for the scale of the tree to be determined, and the scale of the tree can be adaptively expanded during the data-appending phase. Therefore, the DCAT can suit the data stream environment better. During the data querying phase, the average authentication path length has been reduced, which leads to less space requirement and better verification efficiency. Finally, we performed theoretical analysis and drew a comparison between the static CAT and the DCAT in terms of performance. The result indicates that the DCAT provides improvements in the performance of the data-appending, data-querying, and data verification processes.