Abstract: The SEM technique is used to observe and study the microstructure of cement-sodium silicate-stabilized soft soils with different curing time. The GIS technique is employed to realize 3D visualization of the image of SEM and to calculate the porosity of the soils before and after stabilization. The results show that the principal components of cement-sodium silicate hydration products are respectively ettringite in early days and hydrated calcium silicate in later days. The shapes of the hydrated products are mainly fibrous and prismatical. They play a role of reinforcement by attaching each other to form network and enwrapping the soil particles to form greater particles. The micromechanism of cement-sodium silicate-stabilized soft soils is analyzed from both chemical and physical points of view. From the chemical point of view it mainly includes hydrolysis and hydration reaction of cement, rapid hardening and reinforcement of sodium silicate and the effect between clay particles and cement, while from the physical point of view, it includes filling effect, cementation effect, reinforcement effect and skeleton effect. It is of important significance for the design and construction of foundation treatment in soft soil areas.