State/Event fault tree (SEFT) is a modeling technique for describing the causal chains which lead to failure in component-based embedded systems, and the top event of SEFT describes the result of the failure. One important way for capturing the mean time parameter of system failure is to quantitatively analyze the mean time of the top event occurrence, which provides support for system safety evaluation. However, it is necessary to formally describe SEFT semantics in order to quantitatively analyze the time property. In this paper, a time property analysis method for SEFT based on interactive Markov chain (IMC) is presented. Firstly, interface interactive Markov chain (Interface-IMC) is proposed based on refining the interactive action of IMC. Secondly, semantics of components and logic gates in SEFT are formally described by Interface-IMC. Thirdly, the semantics of SEFT is obtained by composing all the Interface-IMCs generated in the above steps. During this process, weak bisimilarity technique is applied to reduce state space. Then, a quantitative time analysis method is presented based on the formal semantic model of SEFT. Finally, the time analysis processes for the SEFT of aircraft radar landing control system and sprinkler system are illustrated by the proposed method. The method provides a new solution for analyzing time properties of component-based system failure.