The existence of time delay causes the operation of supply chain system to aggravate the instability, induce bullwhip effect and reduce overall performance. In this paper, a discrete mathematical model with time-varying delay is constructed to investigate supply chain inventory network system with time-varying delay. Based on the proposed discrete mathematical model with time-varying delay, the inventory control strategy is desgined by using Lyapunov-Krosovskii functional analysis method. The feasibility analysis of supply chain inventory control strategy on bullwhip effect and the influence factors of time-varying delay are discussed by means of numerical simulation. The results prove that the inventory control strategy can restrain bullwhip effect effectively. It provides a novel approach to study supply chain inventory network system with time-varying delay from discrete perspective.INDEX TERMS Supply chain system, bullwhip effect, inventory, time-varying delay, sensitivity analysis.