研究期間：10108~10207;The application of safety factor proves to be an effective and useful approach for engineering design, especially in the field of geotechnical engineering. However, the use of safety factor tends to integrate some common variations and uncertainties of the engineering properties of soils into one numeric value and hence the selection of safety factor is dependent on the experience of the engineers and types of projects. This study aims at exploring the spatial variability of some common engineering properties such as the standard penetration test N values from available soil boring data from different areas in the world, such as southern Taiwan, Kuwait and North America. The total soil borings collected for this study is about 250 soil borings; each area has its characteristics of the soil profiles and properties. The target of this study is to discuss the horizontal spatial variation of the SPT-N values for the first five meters of soil from ground surface and obtain the correlation distance and function in order to describe the spatial variation of each area. Consequently, the characteristic of spatial variation in each area will be compared and discussed based on available results, hoping to provide relevant information for further engineering design when random field modeling is desired.