A chemical-composition sensitive model to predict the creep properties of Ni single crystal superalloys at high temperature ranges is presented, which takes the microstructure characteristics and service conditions into consideration. The minimum creep rate achieved with fully rafted microstructure is simulated as a combined contribution from the dislocation mobility in channels and the penetrating resistance of plates, as well as the dislocation network on interface. The dependence on alloy compositions then arises with the relationship to diffusion coefficient, anti-phase boundary energy and lattice misfit. Ni commercial superalloy grades with a wide range of chemical compositions are employed to test the capability of the model. The results show that creep properties of commercial alloys can be well reproduced against the published experimental data. The application of the model as an alloy design method for novel Ni-based single crystal superalloys with improved creep properties at elevated temperatures is discussed.