Abstract: In fresh water,the difference of temperature and turbidity is an important factor for density difference and density flow. In order to find out the spatial-temporal differences and influencing factors of density flow in Xiangxi Bay,based on the monthly hydrodynamic monitoring data of Xiangxi Bay in 2018,hydrodynamic processes such as water temperature and turbidity are analyzed and the quantitative calculation is carried out. The results show that density flow is mainly caused by the temperature difference and turbidity difference in Xiangxi Bay.In the flood season,turbidity difference is the main reason for density flow in the flood season,and sediment concentration of CJXX and XX00 has a more significant effect on water density than temperature,the contribution rate,which is caused by sediment concentration on water density,is up to 96%. The contribution rate caused by water temperature difference to water density,is more than 95% in each month.When the ratio（The ratio of turbidity difference ΔZD to temperature difference ΔT）is between 167.27 and 357.27,the sediment concentration difference ΔρS generated by turbidity difference is equal to the water density difference ΔρT generated by temperature difference,both of them have the same effect on the water density. When the ratio is less than 167.27,the contribution caused by temperature difference to water density,is significant. When the ratio is more than 357.27,the contribution caused by sediment concentration difference to water density,is significant.