The combination forecasting model based on vectorial angle cosine is a kind of correlation one. It is a new way to study combination forecasting method. In this paper, the basic structural characteristics of combination forecasting model is studied under the criterion of vectorial angle cosine. Firstly, some new concepts, such as superior combined forecasting, dominant forecasting method, redundant degree etc, are put forward; then some questions are discussed, such existence of noninferior combination forecasting, superior combination forecasting and redundant forecasting method. The method of determining redundant information is also given in a theorem. Finally an example is used to show that this model has much applicable value