Abstract: Traditional pile foundations are prone to issues such as "slip piles", "suspended piles", and "semi-suspended piles" in karst development areas, leading to problems such as insufficient bearing capacity and uneven settlement. Based on a project with extensive karst (soil) cave development in Baiyun District, Guangzhou, this paper innovatively proposes a rigid pile composite foundation raft solution. According to the site conditions, the advantages of the rigid pile composite foundation raft are discussed from aspects such as cave treatment, bearing capacity, pile quality requirements, and impact on the surrounding environment. Through the calculation of composite foundation bearing capacity and settlement, analysis is conducted on foundation pile testing data, composite foundation bearing capacity testing data, and tower monitoring data, and the concept of cushion settlement ratio is proposed. The research shows that the cushion effectively coordinates the stress and deformation at the pile top. When the cushion settlement ratio reaches 50% to 60%, it significantly reduces uneven settlement caused by differences in pile length. The thick silty clay layer overlying the bedrock provides high frictional resistance, reducing the dependence on the bearing capacity at the pile tip and lowering the construction risk of traditional pile foundations. Compared to cast-in-place piles, this technology shortens the construction period, reduces costs, and avoids mud pollution, significantly improving the engineering applicability. The conclusion confirms that the rigid pile composite foundation raft has good stress-strain coordination ability, significantly reducing the engineering risks of traditional pile foundations in karst development areas. It provides a safe, economical, and environmentally friendly foundation treatment method for high-rise buildings in karst development areas.