With rapid urbanization in China, a large amount of excavated soil and construction sludge is being generated from geotechnical and underground engineering. For sustainable management of these construction wastes, it is essential to quantify their production first. The present study has attempted to classify the excavated soil and construction sludge according to their composition and geotechnical properties (particle size, water content, plasticity index). Based on these classifications, a new approach was proposed to quantify the production. The said approach was based on multi-source information, such as the urban topographic map, geological survey reports, urban master plan, and remote sensing images. A case study in Wenzhou city of China was also pursued to illustrate the validity of the newly developed approach. The research showed that in 2021–2025, the total excavated soils and construction sludge production in Wenzhou would reach 107.5 × 10⁶ and 81.7 × 10⁶ m³, respectively. Furthermore, the excavated soil was classified into the miscellaneous fill, crust clay, muddy clay and mud with silty sand. Likewise, the construction sludge was classified as liquid sludge and paste-like sludge. The classification and quantification can serve as guidance for disposal and recycling, thereby leading to high-level management of waste disposal.