Abstract: Influenced by overfishing, habitat destruction, and climate change, global oyster reef degradation has become severe, with artificial restoration emerging as one of the most effective measures. In this study, the coastal waters of Shandong Peninsula were selected as the study area. Based on relevant literature, determine the marine environmental, habitat, and socio-economic factors that have significant influences on the growth of Crassostrea gigas and the restoration of oyster reef, while delineating threshold ranges and optimal conditions of related factors. Integrating multi-source data—including satellite remote sensing data (2011—2020), bathymetric data, and socioeconomic data—and using Geographic Information System (GIS), Analytic Hierarchy Process (AHP), and R for spatial overlay analysis and spatiotemporal statistics, a comprehensive suitability evaluation index system for Crassostrea gigas reef restoration along the Shandong coast was developed. This study also investigated the spatiotemporal distribution patterns of suitability and the environmental mechanisms influencing it. The results showed that the suitability of Crassostrea gigas reefs in the coastal waters of Shandong is dominated by medium and low suitability zones overall. High suitability zones are primarily distributed in the southeastern Laizhou Bay, the northern coastal area of Yantai, the Sanggou Bay in Rongcheng, and the southern coastal area of Rushan. The suitability exhibits distinct seasonal characteristics, showing an evolution pattern of “contraction in winter and expansion in summer”. The proportion of area with a suitability index greater than 0.5 showed an overall upward trend, with significant quarterly variations. It exhibited the strongest correlation with Sea Surface Temperature (SST), increasing significantly with rising SST, and a negative correlation with Total Suspended Sediment (TSS). The ecological benefit analysis of the Crassostrea gigas reef based on suitability indicated five potential core habitats in the study area during summer, presenting a relatively uniform patchy distribution. These findings provide a theoretical basis for scientific site selection of Crassostrea gigas reef ecological restoration in the coastal waters of Shandong.