Tension-leg platforms have attracted increasing attention due to their smaller motion responses in platform planes among various offshore floating platforms. To better utilize wind energy sources, this paper carried out an improved modelling calculation for tension-leg floating foundations. A comparative study was conducted on the dynamic responses under environmental loading conditions via altering the tension legs’ connection angle. Based on potential flow theory and the Morison formulation, this paper established a complex system of tension-leg platforms under coupled nonlinear loads. After considering tension legs with different angles under the same or different environmental loads, numerical simulations were performed using AQWA for motion responses. Following this, the restraining effect on the platform motion responses and the tension changes of the tension legs are further discussed. The results indicate that compared with the existing tension-leg connection mode, this paper’s model could effectively reduce the dynamic responses in surge and pitch and improve the stability and safety of tension-leg platforms.