Well-obstruction and daub-effect are often met in the process of consolidation by prefabricated drains for ground improvement and their influences on the degree of consolidation are great. This paper expounds the principle of well-obstruction and daub-effect and the influence to foundation consolidation, analyzes the calculation methods of factors concerning well-obstruction and daub-effect, and points out the differences between these calculation methods and analyzes the rationality of the methods. It provides a reference for the analysis and design of drainage consolidation of foundation improvement.