Abstract: The static cone penetration test (CPT) is an internationally used technique for potential evaluation of soil liquefaction in the world. The common method of CPT is based on the equivalent pure sand and only applicable to sand and low plastic fine-grained soil. The absolute majority of the current CPT liquefaction evaluation methods treat all pure sand (fine particle content < 5%) as the same. In order to solve the above problems, firstly the typical soil classification curves and liquefaction discriminant curves are reviewed using the CPT parameters. Based on the spatial similarity of soil classification index curves and liquefaction discriminant curves, the model for the liquefaction discriminant slope method and the liquefaction discriminant curve of soil classification charts are proposed based on the Bayesian updating technique and likelihood estimation. The results show that the cone tip resistance of CPT in the proposed model is converted to the corresponding value of the equivalent pure sand without fine-grain content estimation or testing. The soil classification index, I_c can reflect the compressibility of soil, and the factors affecting the penetration resistance (such as density, overconsolidation, etc.) are also taken into account. The soil classification charts and soil classification index combined to modify the cone-tip resistance can be effectively used for liquefaction evaluation. Finally, an example is given to verify the correctness of the proposed model.