In order to investigate the structural deformation and motion response of large flexible floating collar in waves, a model test is conducted in a towing tank for both regular and irregular wave conditions. The floating collar model is fixed horizontally to the trailer using four steel cables, the displacements of the test points on the collar are captured using the Qualisys system, and the mooring force is measured using a single force sensor, while the wave elevation near the model is recorded by wave gauges. The Response Amplitude Operator (RAO) of the vertical and longitudinal motions of different locations on the floating collar under regular waves is analyzed by test, the spectral analysis is conducted for the motion and deformation of the floating collar under irregular waves, and the responses of the mooring force under both regular and irregular waves are explored. The results show that: the wave heights on the downstream side of the model are significantly lower than those of the incident waves; the elastic deformation of the floating collar exhibits different modes at different frequencies; the vertical motion response spectrum of the floating collar shows that the amplitude at the upstream side is greater than that at the downstream side, while the lateral point is of the smallest amplitude; the mooring force spectrum decreases with the increase of the incident wave frequency in the low-frequency range, and there is a second peak above the wave frequency. The study offers meaningful insights into the dynamic behavior and hydrodynamic response of large flexible floating collar under different wave conditions.