Abstract: How to choose reasonable policy for ordering consumable spare parts is an effective approach to reduce inventory cost and improve equipment support effectiveness. For the existing typical three-echelon supply mode of military equipment, this research establishes a cooperative ordering model with the inventory ordering theory of cooperative supply chain system under (<em<R, Q</em<) inventory policy. When the stochastic ordering is requested with time delay, the Lagrange multiplier is introduced to decompose the model, which could be solved by heuristic algorithm. For a given example, the obtained optimal result is consistent with the practice and the factors that affect result could be analyzed. The presented method could provide decision making for personal support to design a reasonable ordering project.