We study an integrated supplier chain consisting of a vendor and multiple buyers. We assume that, in order to coordinate the supply chain and achieve high efficiency, the vendor adapts Vendor Managed Inventory (VMI) policy. Demand is modeled as a deterministic linear demand function where buyers’ markets are non-identical. We consider the supply chain problem where the lengths of buyers ordering periods are the decision variables in the optimization model. In our setting the vendor produces multiple items. To facilitate the production planning, the vendor imposes the joint replenishment policy for its buyers. In this paper we present a model of two-echelon single-vendor multiple-buyers supply chain model with multiple items and under joint ordering policy. We analyze the model carried out with a numerical study. To validate the model, we solve some numerical sample problems by GAMS optimization software. Then, we study the sensitive of the model with respect to model’s parameters.