complex optimization problems，capabilityof global search is decreased in the later evolution period，and the ability of global search is weakened and algorithmcan easily fall into local optimum. In response to these problems，stagnation factor and similarity factor are defined.Scaling factor F is adaptive adjusted according to the stagnation factor. Similarity between individuals is determinedby the similarity factor，the gene reconstruction is taken. So that the problem of decrease of population diversity canbe alleviated. The improved algorithm is applied to standard test function optimization and vehicle routing problem，the results show that improved differential evolution algorithm has better global search ability. And the algorithm issuitable for solving complex optimization problems.