To save the developing and whole lifetime using cost of automatic test equipment, and attain the highest costeffectiveness ratio, from the perspective of the whole test support system, a model is established for military automatic test equipment renewal based on mixed integer linear programming, which is grounded on analysis of unit under test demand, cost of automatic test equipment and lifetime of equipment on active service into consideration. According to the needs of a certain military plane in the test, this paper analyzes the renewing decision problem under different baseline costs. Compared the influence on the sensitivities of a variety of factors from the renewed outcomes, the outcomes of different lifetimes setting are also acquired. The outcomes show that 5 to 7 times of baseline cost are the critical renewing points of corresponding test equipment of 98％ the number of units under test, the renewing decision is mostly effected by transplanting cost, and the outcome of renewing decision is obviously affected by prolonging the lifetime of new equipment to 20 years.