We proposed a new creep constructive equation to express the characteristic “S-shape” primary stage for Ni-base single crystal superalloys. In this report, parameters of the creep constructive equation for alloys of various compositions were analyzed by multi regression method, and the results were discussed in terms of the chemicel compositions and structural parameters of the alloys. The creep constructive curve was fitted to a creep curve at 1100°C, 137 MPa for each of 23 kinds of Ni-base superalloys. On the basis of the fitting results, multi regressions for each parameter were made with gamma-prime composition, lattice misfit and volume fraction of the gamma-prime phase as explanatory variables. This result enables the prediction of a creep curve of an alloy directly from its composition. Moreover, the effectiveness of alloying elements for the creep behaviours, especially during the primary stage, can be evaluated by the multi regression analysis.