Abstract: A rafting model for creep of Ni base single crystal based on microstructure cell was introduced into the dislocation slip model, and the rafting behaviors during creep of DD3 at 1 223 K and SRR99 at 1 123 K and 1 253 K were described in combination with the cell's analytic stress model.By incorporating the changes of the cell's dimensions into the cell stress model, the criterion of rafting type and direction judgment was determined and the rafting deformation was simulated quantitatively.Both the results of rafting direction judgment and the simulation of rafting process were in agreement with experiments.With the introduction of rafting model, the dislocation slip model could simulate the creep behavior of single crystal at high temperature more accurately.