The microstructure feature values included fractal dimension of grains, fractal dimension of holes, porosity, total area of poles, number of holes, average circle of holes, average area of holes, complicated degree of holes, and average diameter of holes. A new technology comprised of the liquid nitrogen refrigeration sample-made technique (LNRSM), the scan electronic microscope technique (SEM), and the image processing, analysis, computer vision technique (IPACV) introduced in geotechnical engineering research. Using this technology, the microstructure feature values extracted from 46 groups samples. Meanwhile, the engineering indexes which included compression coefficient, compression module, cohesion and internal friction angle have also withdrawn based on traditional experiment method. The research results between microstructure feature values and engineering indexes discovered there are some relations which proved effective to explain engineering properties of saturated soft soil with microstructure feature values.