The measurement of the close time is the key task of planning the time-sensitive target kill chain（TSTKC）. Ignoring the overlapping relationships among the steps of TSTKC， previous studies have adopted methods based on linear accumulation. This paper proposes a dynamic measurement method for the close time of TSTKC based on overlapping relationships additionally. Simulation results show that this method is more accurate， which is helpful for the command organization to capture more strike opportunities. The method also adapts to the changes of the window of vulnerability， which can provide a theoretical basis and technical support for the construction， modelling and effectiveness evaluation of TSTKC.