The KKSO multi-phase field model is employed to simulate the lamellar-rod transition with different pulling velocities and different solute diffuse coefficients in liquid. The simulation results show that the eutectic keeps lamellar growth after lamellar merging at small pulling velocity. With an increase of the pulling velocity, the lamellar eutectic transits to rod-like eutectic after lamellar merging. And the further increase of the pulling velocity will make the lamellar grow steadily with its initial lamellar spacing. It's also found that the simulations of different solute diffusion coefficients in liquid are similar to those of different velocities and the transition from lamellar eutectic to rod-like takes place only in a certain range of each parameter. All of the simulated results are in agreement with the experiments qualitatively.