Abstract: A method was proposed to solve the group decision making problem with preference information in ordinal interval form. Firstly, a description of the group decision making problem with preference information in ordinal interval form was given. Then, according to the basic thinking of tranditional Cook-Seiford function to solving group decision making problems, the calculation steps were given to solve group decision making problem with preference information in ordinal interval form, where the key point was to define the distance (s) between the rank (s) of group and the rank of each expert, and in order to find a rank of the group which has the smallest distance with the rank of each expert, a linear optimization model was constructed to obtain the ranking results of alternatives. Finally, an example was used to illustrate the feasibility and effectiveness of the proposed method.