Micro simulation of solidification process is one of the focuses in material field, and simulation on microsegregation forming has important effect on directing materials processing. But papers about this field were seldom found on domestic publications. Influence of micro time steps on microsegregation simulation results was investigated in this paper and it is pointed out that the relation between the micro time steps and the microsegregation simulation results is weak for iterative method based microsegregation simulation. It is not necessary for using a large number of micro grids to converge the calculated results.