This study takes a certain foundation pit support project as a case study to explore the accurate measurement method of earthwork based on BIM technology. In the study, drone oblique photography technology was used, combined with relevant BIM software, to achieve accurate extraction of terrain surface elevation points, 3D modeling of geological bodies, and creation of foundation pit models. Through the application of BIM technology, not only has the efficiency and accuracy of earthwork calculation been improved, but the limitations of traditional manual measurement have also been overcome, achieving effective integration of multi-disciplinary digital information. The research results indicate that BIM technology has significant advantages in earthwork volume calculation, which can more effectively utilize the combination of multiple technologies, improve the authenticity and effectiveness of data, and promote the flow of information between professions and the flow of data between software platforms.