This paper investigates the supply planning of two-level and multi-period inventory control with stochastic lead time and random machine breakdown. Due to the probability of lead time, the actual lead time may be longer than the planned time in each production cycle, which will delay the delivery of the final product to the final customer. And it is also possible that the final product will be ready to be delivered to the customer sooner than the specified time, in which case the product is maintained and delivered to the customer at the specified time, which imposes additional maintenance cost on the production system. Also, due to the random machine breakdown, the machine may break during production or outside the production cycle. Demand for the final product and the policy of supplying demand is considered as periodic order quantity. The purpose of the problem is to determine the planned lead time and time interval between production orders based on periodic order quantity policy and uses the genetic algorithm to minimise the total system costs. Finally, a numerical example is explained, based on which the main parameters of the proposed model are analyse
