This study aims to propose an assessment model for environmental economics that will provide useful information for decision-making on the implementation of pro-environmental and economical construction projects. To meet this objective, this study suggests a procedure for estimating the environmental cost of construction projects. The model combines environmental load assessment and environmental value assessment. The environmental cost of pollutants generated from a construction project was estimated utilizing Contingent Valuation Method (CVM), a value assessment method borrowed from economic science. A case analysis was subsequently conducted to verify the applicability of the proposed model to actual construction projects. The devised model is expected to provide a useful methodology that will scientifically support the planning and management of sustainable construction not only in terms of the environmental aspect but also of the economical aspect.