Abstract: In the oil/gas exploitation of Bohai Sea,the physical and mechanical properties of sea ice are important to determine the design parameters of offshore structures,and also have important influence on the ice dynamics.With the increasing applications of ice-breaking conical structures,the investigation of sea ice flexural strength is more valuable since it is the most important factor to calculate the ice force.In this study,the sea ice flexural strengths were measured in situ and in door around the Bohai Sea at nine sites.Meanwhile the salinity,velocity and loading rate were also measured in the experiments.The characteristics of sea ice flexural strengths were analyzed at the Laizhou Bay,the west shore of Liaodong Bay,and the east shore of Liaodong Bay.Finally,the influences of brine volume(salinity,temperature) and stress rate on the sea ice flexural strength were analyzed.Based on the linear function between flexural strength and stress rate,and the negative exponential function between the flexural strength and the square root of brine volume,a double-parameter equation is established to determine the sea ice flexural strength.This study can be used to determine the ice load on the conical and slope structures in ice-covered regions.