Abstract: In this paper, based on a large number of comparative tests between conventional tests and cone tests on the undisturbed and remolded clayey soils, a new approach to determine the indexes and characteristics of clays is proposed. This method is very simple and rapid, and all the tests of liquid limit, plastic limit, natural consistency, liquidity index, sensitivity, the unconfined compressive strength and undrained shear strength of undisturbed and remoulded clays can be finished within an hour by one operator. According to conventional test procedures, the determination of this characteristics takes several days or even weeks. In addition, the relation between cone penetration and shear strength are analyzed and the strength corresponding to liquid limit, plastic limit and various liquidity index are also given in this paper.