In this paper, the nonlinear vibration responses of a dual-rotor system supported on the ball bearings considering coupling misalignment are investigated with inevitable uncertainties included. Moreover, uncertain parameters are modelled by non-probabilistic interval variables, alleviating the hash demands in fitting into a sophisticated probability law. It is then more suited for engineering problems that have sparse prior data on uncertainties. The deterministic vibration responses, orbits and frequency spectrum are provided first to exhibit the evolution of the vibrations. Then, several physical parameters are studied to reveal the effects of their uncertainty on the nonlinear vibrations at different rotating speeds. It is worth noting that uncertainty in the speed ratio between the higher-pressure and lower-pressure rotors has great impacts. Moreover, the sensitivity also depends on the rotating speed.