K0 consolidation(confined consotidation) can induce soil anisotropy. To investigate the effects of structures on the normalized undrained strength and strength anisotropy of K0 normally consolidated soil, triaxial ACUC（K0 consolidated compression）, ACUE(K0 consolidated extension) tests and direct shear tests were conducted on natural specimens and remolded specimens of Shanghai soft clay. It was found that in the triaxial ACUC and ACUE tests, in the range of consolidation pressure of up to 3.7 times structure yield stress, because of structure effect, the natural specimens have different effective stress paths, ultimate strength line, effective internal friction angle, and normalized strength with the remolded specimens. When consolidation pressure is small, the natural specimens have a larger ACUE strength and therefore, a smaller strength anisotropy than the remolded specimens. With the increase of consolidation pressure and structure damage, the strength anisotropy of natural specimens increases gradually and approaches the strength anisotropy of remolded specimens. Therefore, in the research of the normalized ACUC，ACUE strength, and strength anisotropy of natural soft clay, structure effect should be taken into considered. Moreover, it is found that the two kinds of specimen have almost the same normalized direct shear strength, therefore the effects of structures on direct shear strength can be neglected.