The development of Constant Plastic Index (CPI) method is an approach model based on the theory of consolidation. The objective behind the development CPI method is to predicts critical state settlement whereby CPI is to achieved secondary settlement and reduced time of consolidation. The development CPI has been derived base on the ultimate soil settlement where soils are classified accordingly using initial void ratio, final void ratio and thickness of soil layers. The linear and non linear soil was developed by the relationship between an exponential stress - void ratio and the parabolic permeability - void ratio. The external forces is normally consolidated soil layers and develop Stratum index factor (SIF) and Void ratio function(VRF) which is composed of such a soil varies non- linearly in deposition. Development of CPI will used to predicts critical state settlement, using Eurelian method By combination of these elements, the Potential Instability of settlement was develop and integrate CS- Rating makes concerted effort to produce CS- statement guidelines and better design strategy for geo -mechanics engineer to involve in soil development settlement analysis. Finally, modification of CPI method can be determine soil settlement by using CS- Rating. © 2016, Int. J. of GEOMATE.