The vibration of the rotor with the loose support increases abnormally due to the asymmetry of the stiffness at both ends, which may lead to the crack fault of the rotor. The rotor system under the coupling of the crack and the loose faults shows the strong nonlinear characteristics. The dynamic model of the rotor with the pedestal looseness-crack, supported by the rolling bearing is developed, and the effect of the rotational speed, the loose clearance, the loose mass and the crack angle on the nonlinear dynamic response of the rotor system is studied. Considering the nonlinear Hertz contact force, the breathing crack model is applied in this study and the piecewise linear equation is used to describe the stiffness and damping of the loose pedestal. The dynamic equation for the rotor system is formulated by using the Lagrange equation. The equation is solved using the Runge-Kutta method to get the bifurcation diagram, the spectrum diagram, the axis trajectory diagram, and the Poincaré diagram of vibration response for the rotor system. The research results show that when the rotating speed increases up to 2300rad/s, the looseness-crack coupling fault system has obvious interharmonic components at 1/3 frequency division and the chaotic region is wider compared with that of only crack rotor system. When the crack parameters are constant, the system will be more stable with the decrease of the loosening gap. When the loosening mass ms is greater than 41.25 kg, the amplitude of the system increases sharply, and the jumping phenomenon occurs. The research work has important engineering application value for the fault diagnosis and the health monitoring of the looseness-crack rotor system.