Pearl River Delta region in China has developed economy and buildings are “changing with each passing day”. However, most of the area is a soft soil foundation. Solving the soft foundation problem has become one of the major tasks of urban construction. Combining the two commonly used soft foundation treatment methods: the stack consolidation method and the cement mixing pile method, relying on a soft foundation reinforcement project for on-site test, respectively adopting the “first pile then stack” process (first cement mixing pile, then stack consolidation) and “first stack then pile” process (first stack consolidation, then cement mixing pile) to treat soft foundation. Through the use of the core drilling method, the standard penetration test and the unconfined compressive strength test of the core sample of the pile, the influence of the two processes on the quality of the pile is explored. Meanwhile, monitoring of the earth pressure and the static penetration test before and after the reinforcement as well as the lateral displacement situation are explored to study the different effects of the soil between the two processes. The research results show that the pile strength after the construction of “first stack then pile” is high, but the strength of the pile after the two treatments both meets the design requirements. The strength of the soil between the piles after the “first stack then pile” process is high, but the process has a great impact on the environment and the construction period is long. The soft foundation after the “first pile then stack” process has a certain bearing capacity, and has little impact on the surrounding environment as well as short construction period, and has certain engineering application value. Therefore, “first pile then stack” is recommended to be applied to the soft soil foundation of general buildings.