Assessing the health of coastal ecosystems is crucial for maintaining ecological balance. One significant indicator of water eutrophication is the distribution of chlorophyll-a(Chl-a), which makes obtaining a complete three-dimensional spatial distribution of Chl-aessential for assessment. This study utilized the linear radial basis function (RBF-Linear) method to obtain a comprehensive and reasonable spatial distribution of Chl-a. The method was applied to obtain the three-dimensional spatial field of Chl-aconcentration in the Bohai Sea in March, May, August, and October from 2016 to 2018. The distribution pattern of Chl-aconcentration in the Bohai Sea displayed characteristic spatial and temporal variations. Spatially, high Chl-aconcentration was most concentrated in coastal waters, particularly in estuaries and mariculture areas. Temporally, there were two peaks in March and August. The total Chl-aand areas with high Chl-aconcentration in four sub-regions of the Bohai Sea were also calculated to enable a comprehensive assessment of the marine ecological environment. By analyzing the temporal and spatial variation of Chl-ain the Bohai Sea and evaluating the marine ecological environment, we confirmed the feasibility and rationality of RBF-Linear. Our findings have the potential to contribute to improve the accuracy of ecological models and assessment of the satellite products.