False data injection attacks (FDIAs) have recently become a major threat to smart grids. Most of the existing FDIAS detection methods have focused on modeling the temporal relationship of time-series measurement data, but have paid less attention to the spatial relationship between bus/line measurement data, and have failed to consider the relationship between sub-grids. To address these issues, we propose a sub-grid-oriented microservice framework by integrating a well-designed spatialtemporal neural network for FDIA detection in AC-model power systems. First, a well-designed neural network was developed to model the spatial-temporal relationship of bus/line measurements for sub-grids. A microservice-based supervising network is then proposed for integrating the representation features obtained from sub-grids for the collaborative detection of FDIAs. To evaluate the proposed framework, three types of FDIA datasets are generated based on a public benchmark power grid. Case studies on the FDIA datasets show that our method outperforms state-of-the-art methods for FDIA detection in these datasets.