In order to study nonlinear vibration responses of a shrouded blade with friction contact interfaces， a fractal friction contact model is developed to calculate the friction force with surface roughness based on three-dimensional micro-slip friction model being considered. In this model， the friction contact interface is discretized to a series of friction contact units， and each of them is represented by a friction contact pair which can characterize stick， slip， or separate states. The topography of contact surfaces is simulated by fractal geometry. The contact stiffness and friction coefficient are calculated using the fractal geometry and Hertz contact theory， which are related to surface roughness， normal load， Young’s modulus and Poisson’s ratio. The friction force is calculated by contact stiffness， friction coefficient and the relative displacement of friction contact pairs. The forced response of a real shrouded blade is predicted using the developed model. The effects of surface roughness and initial normal load on the forced response of a shrouded blade are investigated. It is shown that the current model can predict response of a shrouded blade considering surface roughness. The contact stiffness and friction coefficient vary with surface roughness， which affect friction forces. In the present model， the contact stiffness increases with normal load and decreases with roughness， while the friction coefficient increases with normal load and increases at first then decreases with roughness. The resonant amplitude of the shrouded blade can be significantly affected by the initial normal load and contact surface roughness.