As there are some jumping errors from the differential equation to differential equation in traditional grey modeling,this paper proposed recursive solution to unbiased grey model based on the unique expression of such models.It deduced prediction formulas of unbiased grey model under different initial conditions with the recursive method.On this basis,further study of the optimization problem under two criteria has been done.The results show that both the optimal models under the same criteria have the same simulation and prediction values with higher precision than other methods.Finally,the effectiveness and the practicality of the model are proved by a real project.