The destruction effect of the terrorist explosion attack on the subway tunnel involves large-scale fluid and structure interaction, and the detailed structure has a great impact on the damage form. A fully coupled numerical model of subway carriage, considering the influence of the subway structure on the explosion flow field and the damage pattern of the carriage, was established based on the Lagrangian-Euler coupling algorithm. The propagation characteristics of the explosion shock wave and damage mechanism of the carriage were studied. The influence of the carriage body, the window and charge weight on the response of the subway structure were investigated. Besides, the blast resistance property of the subway tunnel by choosing aluminium foam as the blast protection measure was also analyzed. The results show that the attenuation of the shock wave versus time and space under the combined constraint effect of train and tunnel is much slower than that in tunnel without carriage. The pressure and impulse close to the explosive charge without the window are twice and 2.32 times of the carriage with windows, respectively. The aluminium foam can significantly reduce stress level of the subway tunnel and make the stress distributed evenly, which has a better mitigation effect on the blast wave in the close range.