Railway subgrade design and construction is an important part of railway infrastructure construction, which plays an important role in ensuring the safety and efficiency of railway operations. However, there are a series of problems and challenges, such as low design efficiency, difficult construction quality monitoring, poor design and construction coordination, which cannot adapt to the needs of efficient, accurate and sustainable railway subgrade construction. The rapid development of BIM technology, as a new design and management tool, has become an important auxiliary technology for modernized railway subgrade design and construction, which brings great opportunities and challenges for the railway subgrade. This paper studies the application status of railway subgrade design and construction based on BIM technology and discusses the challenges and development trends. It found that BIM technology in railway subgrade design and construction has the advantages of improving design accuracy, reducing errors and conflicts, and optimizing construction management. However, there are a lot of challenges in technology, organization and management, and legal aspects. In the future, BIM technology in railway subgrade design and construction will develop in the direction of intelligence, collaboration and digitalization.