Adopting the similar simulation method, a laboratory model has been established on the basis of original box where wood and coal are seperated,the optimization test to the structural parameter of seperating box has been done. The result shows that the expectant goal to reduce impurity clearly with little coal can be achieved.[Descriptors] Separating box Optimization test Structural parameter Adopting the similar simulation method, a laboratory model has been established on the basis of the original box where wood and coal are seperated, the optimization test to the structural parameter of seperating box has been done. with little coal can be achieved. [Descriptors] Separating box Optimization test Structural parameter