Mud performance is of great significance to ensure the quality and safety of underground diaphragm wall construction.Orthogonal test is used to analyze the relationship between mud performance index and sediment thickness.Based on the correlation between mud performance and salt concentration,influnce factors of mud performance under high salt conditions are discussed,suitable mud mix proportions are determined for different geological conditions in the construction area.The results show that the sediment thickness of the construction area near the sea is thicker and the time for the sediment to reach stability is longer.The greater the density,viscosity and sand content of mud are,the greater the final sediment thickness is,and the increase of density and viscosity will prolong the time for sediment to reach stability.Mud density is positively correlated with salt concentration,while viscosity and pH are negatively correlated with salt concentration.Mud performance can be controlled by adjusting the mix proportion of mud materials.Sodium bentonite will increase the mud density,viscosity,sand content and pH value,soda ash will increase the mud viscosity and pH value,and polyaluminum chloride can increase the mud density and reduce the mud sand content and pH value.In the high salt environment near the Red Sea area,the recommended mud mix proportion is 10% sodium bentonite,0.2% soda ash content,0.08% polyaluminum chloride,89.72% water with pH 8.