Distributed storage system is receiving more and more attention in mobile network scenarios. Data placement, a key technology of distributed storage, is crucial to improve the success rate of distributed data storage. However, due to unstable wireless signals and fluctuating network bandwidth in mobile environments, the traditional data placement strategies, such as random placement strategy and storage-aware placement strategy, have low success rates of data transmission because both of them do not take network bandwidth into account during data placement. To solve the problem faced by mobile distributed storage systems, this study proposes a bandwidth-aware adaptive data placement strategy (BADP). The main breakthrough is that BADP adopts the group mobility model to sense the network bandwidth of nodes and takes the network bandwidth as an important factor for data placement, thus selecting nodes with good performance to achieve adaptive data placement and improve the success of data transmission. BADP consists of three design features: (1) adopting the group mobility model to sense the network bandwidth of nodes; (2) managing node information in groups to reduce communication overhead, and taking advantage of the heap to build a node selection tree; (3) selecting nodes with good performance using adaptive data placement to improve the success rate of data transmission. Experiments show that when the network changes dynamically, BADP gains at least 30.6% and 34.6% improvements in the success rate of data transmission compared with random placement strategy and storage-aware placement strategy. At the same time, it consistently keeps communication overhead low.