In some cases of multi-attribute decision-making problems,the indexes always vary with time.By increasing the dimension of the problem more reasonable and better decision can be made and the disadvantage of considering only two dimensions of index and scheme can be effectively overcome.In the paper,the three-dimensional group decision-making method is proposed and detailed steps of the method are presented.In considering the time effect,with this method the data in recent years can be analyzed more efficiently in the illustrative examples,and will give overall reliance to decision-maker for making correct choosing.