Abstract: Study on planktonic bacterial communities between bacterial community structure and adhesion characteristics of Liaohe estuary waters and environmental factors and the correlation between changes in the salinity gradient through MiSeq high-throughput sequencing. Environmental factors include salinity (S), temperature (T), dissolved oxygen (DO), suspended solids (SS), chlorophyll a (Chl a), bacterial productivity (BP), chemical oxygen demand (COD), nitrate (NO₃-N), phosphate (PO₄-P), Portland (SiO₃-Si) and ammonium (NH₄-N). Salinity in different regions select representatives Liaohe surface stations and its seawater environmental factors, microbial diversity index, similarity, structure and composition were analyzed. The results showed that S and Chl a increased gradually during the estuary to the offshore waters DO, BP, COD, and N, P, Si nutrient concentrations decreased. Freshwater estuary regionβ-Proteobacteria numerical superiority, the number ofαandγ-Proteobacteria Proteobacteria sea area is gradually increasing. Community structure and environmental factors correlation analysis showed that planktonic bacteria are more sensitive to changes in environmental factors, and changes in bacterial adhesion is less sensitive to environmental factors. Bacterioplankton abundance and S, PO₄-P and BP were significantly correlated (P < 0.01), the correlation coefficients were-0.963, 0.996 and 0.995; SS attachment of bacteria abundance and relevance of the most significant correlation coefficient to 0.997 (P < 0.01), in addition with NH₄-N and Chl a also a significant correlation. Experimental results show that S, PO₄-P, BP, DO and COD are affecting the abundance of planktonic bacteria factor, bacterioplankton abundance and SS, NH₄-N and Chl a closer relationship. In terms of the relative attachment of bacteria, planktonic bacteria play a more important role in the estuarine ecosystem material circulation and energy flows.