This study investigated the increasing strength and permeability of colluvium soil as soil cement using phosphate magnesia cement for the purpose of strengthening soft ground by increasing the strength of colluvium soil which has very weak soil quality. The experiment results show that when colluvium soil solidified using phosphate magnesia cement was applied to soft ground with high water content, the evaporation of water could be accelerated by hydration heat. Therefore, it is expected to be effective for the solidification and stabilization of soft ground. Furthermore, when phosphate magnesia cement was used for colluvium soil at the uniaxial compressive strength of 0.05MPa, the uniaxial compressive strength at the age of 28 days increased approximately 40 times to 2.16MPa. When phosphate magnesia cement at 40wt% was mixed with colluvium soil with the permeability coefficient of $1.0{ imes}10^{-6}cm/sec$, the permeability coefficient improved to $1.4{ imes}10^{-8}cm/sec$ and the soil changed to impermeable solid matter. Therefore, it can be used as an environmentally friendly soil cement.