Building Information Modeling (BIM) implementation brings many benefits for different stakeholders, but how to evaluate the benefits is still an unsolved problem. For dealing with the problem, this study proposes an overall benefit evaluation structure for BIM implementation, and then develops a subjective benefit evaluation model for immature BIM-enabled stakeholders by evaluating project-based benefits in three evaluation stages: pre-project, in-progress and post-project evaluations. Through an empirical study of thirteen BIM implementation cases in Taiwan, this study concludes that the proposed model is appropriate to evaluate project-based benefits for a stakeholder who is not familiar with BIM implementation. The research outcomes and findings of BIM benefits evaluation can assist those in the public and private sectors who have sensed the value of BIM and want to implement BIM technology. Further research to evaluate BIM benefits in different BIM implementation levels is needed.