An index system is built for evaluating knowledge absorptive capability of an enterprise. With this system，a knowledge absorptive capability evaluation model based on the binary interval number theory is establish. Firstly，a multiple criteria decision making matrix is built and standardized；Secondly，using cosine formula to determine the cosine of angle between each indicator of all the company and the ideal indexes to establish cosine matrix. Then with the help of the improved analytic hierarchy process to determine the weight coefficient range of evaluation index；Finally，according to the proposed evaluation index system and evaluation model to evaluate the absorption capacity of four companies and illustrate the applicability and effectiveness of the proposed approach.