Objective To make the stent expand uniformly along the axial, an improved kriging optimization algorithm is applied for to the optimal design of stent-balloon system to find the optimal length of the balloon. Methods Based on finite element method results, kriging surrogate model combining with Latin hypercube sampling (LHS) approach and expected improvement (EI) function was employed for the optimization of balloon length to reduce stent dog-boning effect during its dilation. Results The kriging surrogate model could approximately establish the relationship between stent dog-boning rate and balloon length and so to replace the expensive reanalysis of stent dilation. Sample points from LHS could perfectly represent the vector space. EI function could be used to effectively find out the global optimal solution with high probability. The optimal length of balloon could make the stent expand uniformly. Conclusions This adaptive optimization method based on kriging surrogate model can optimize the design of stent–balloon system effectively.