This paper describes influences of normal stress, shear displacement rate, consolidation and shear stress histories on residual strength of undisturbed and artificially cemented clays having cementation. A series of reversal box shear tests was carried out on undisturbed and remolded samples of 3 landslide clays, remolded sample of kaolin, remolded and intact samples of kaolin mixed with ordinary Portland cement. As a result, the residual strength of the samples with cementation is as same as those without cementation. The residual strengths of the undisturbed and the cemented samples, as well as the remolded sample, linearly increase with increasing the shear displacement rate. The residual strengths of the undisturbed and the cemented samples are not affected by consolidation stress history.