| A theoretical model of steady-state curve negotiation of coupled bogie for straddling monorail vehicle was established, the mechanism of radial adjustment of the coupled bogies was analyzed, and the formula for calculating the coupling parameters required for achieving the radial state was derived. The dynamics model of straddling monorail vehicle equipped with coupled bogies was established, and the curving performance of the coupling bogie was simulated, and the radial adjustment capacity of coupled bogie was verified. Meanwhile, the influence of coupling parameters on the radial adjustment capacity and curving performance of the coupled bogie was also analyzed. The results show that the optimal rotary stiffness is only related to the vehicle structural parameters and the secondary longitudinal stiffness. The reasonable selection of the coupling rotary stiffness can make the coupling bogie automatically reach the radial position on the circular curve under the joint action of the secondary suspension system and the coupling mechanism. At this time, the maximum radial force of guiding wheels is obviously reduced, and the curve passing safety of the vehicle is significantly improved. The coupling lateral stiffness has little effect on the steady value of the yaw angle of the coupled bogie, but it will worsen the dynamic performance of the bogie on the transition curve.