Impact assessment test for large-medium sized shipboard equipment should be carried out through the floating shock platform, and the structure form of the floating shock platform can make the difference between a successful or unsuccessful test. But the IFSP (intermediate floating shock platform) has not been started the construction in China. So the structural design of IFSP is analyzed. The response of the IFSP is calculated through nonlinear doubly-asymptotic approximation. Several structure forms of the floating shock platform are put forward and their strength and shock environment are analyzed. The results show that the main response of the IFSP is the rigid body motion and the structure form of IFSP with box girder and outer plate dissection has the best strength. The spectrum displacement and spectrum velocity of shock environment provided from the inner bottom are consistent with the specification. The spectrum acceleration requires the filtering of deck simulator to meet with the specification. Analysis results are expected to be useful for the construction of IFSP for the impact assessment of large-medium sized shipboard equipment.