Abstract: Physical effects are easy to be coupled in the system design of complex multidisciplinary product.In this paper, an efficient recognition method is proposed to find out the undesired coupled physical effects in the design.This method mainly includes the following steps.First, the physical effect and component are modeled with physical semantics to support qualitative physics-based reasoning.Second, the output flow of component is calculated to obtain the distribution in the local influence area.Third, the undesired physical effects are recognized by checking triggering conditions.The hairdryer example is used to demonstrate the method.And the experimental result shows the effectiveness of the proposed method.