Aimed at the disadvantages of simple construction and attack mode in study of the Command Information System (CIS) cascading failure, a CIS bi-layer coupled network model is constructed. We analyze some characteristics of CIS cascading failure by setting different attack modes based on it. Firstly, the model is constructed by coupling communication network and function network of CIS architecture, and the node weightiness parameter is proposed based on the multilayer network theory. Secondly, by setting three attack modes and defining attack intensity, we analyze cascading failure mechanism of the bi-layer coupled network model. Lastly, simulation results show that the bi-layer coupled network model can reflect characteristics of CIS network structure, and based on this model, we can analyze cascading failure mechanism of CIS under conditions of setting different attack modes and attack intensities.