With the transformation of China's construction market from the incremental era to the stock era, all kinds of engineering reinforcement and reconstruction projects are increasing day by day, among which foundation reinforcement is particularly important. Based on studies on several typical engineering cases for reinforcement, this article introduces the specific application schemes, calculations, and characteristics of root piles in various existing foundation reinforcement, and proposes several composite reinforcement forms. This article analyzes the pros & cons and applicability of the root pile reinforcement method. The study shows that the root pile has extensive applicability in the reinforcement of building engineering foundation. This paper can provide reference for the reinforcement design of many similar projects.