Abstract:Mechanical properties of red clay are related to stress variation and stress state. By using the conventional direct shear test and triaxial shear test,the original stress state,relationship of stress-strain and strength of natural clay can not be reflected actually. Instead,by adopting test with different stress paths,the stress and strain relationship of the real loading process is analyzed. The study results show that in an actual project,the stress paths should be determined according to load case and stress state so that the mechanical parameters of red clay can be measured correctly and reasonably.