To solve the problem of stockout， increasing inventory level and the fluctuation of order quantity caused by stochastic disturbance， an optimization model of inventory system under stochastic disturbance based on Active Disturbance Rejection Control （ADRC） was proposed. Firstly， according to the operational management logic behind the purchase-sale-storage product and information flows， the transfer function of the inventory system was obtained and transformed to a second-order state space standard form by the Laplace transform. Secondly， an optimization model of inventory system under stochastic disturbance based on ADRC including the tracking differentiator， the extended state observer and the nonlinear state error feedback control law was designed to control and compensate the adverse effects on the inventory system caused by stochastic disturbance under the premise of ensuing system stability. Finally， simulations were carried out by using data collected from the industry to verify the effectiveness of the optimization model on optimization of the inventory system under stochastic disturbance. Simulation results show that compared to the inventory feedback control model without ADRC， the optimization model of inventory system under stochastic disturbance based on ADRC has the residual inventory reduced by 40%， the average order quantity reduced by 47.4%， the order fluctuation decreased by 39.3%， and the stockout of enterprise inventory system caused by stochastic disturbance greatly improved. It can be seen that the optimization model of inventory system under stochastic disturbance based on ADRC can guide enterprises to make a reasonable ordering decision， decrease the inventory level， improve the stability of inventory system dynamically， and provide the scientific theoretical reference and countermeasures for the actual operations of enterprises.