Abstract: A method of synthetic assessment for earthquake site with considerations of the effects ofstiffness of site soil, depth of overlying soil, soft intettjedded layer and liquefaction layer is presented.Site index μ is firstiy detennined by synthetic assessment with fuzzy inference according to the stiffnessof site soil（the average shear modulus G）and depth of overlying soil（H₀）. Value of μ is defined as thehasic index of measurement of the earthquake site effect. Relabonship betwen μ and the low frequencyturing period T_v, and hence the design earthquake rpectrum can be shown by the formula T_v=0. 65-0.45μ￣（0.4）. Amending method with consideration of effects of soft interbedded layer and li-quefaction layer on site index and design earthquake response spectrum is aiso presented.