Abstract: In this paper,the periodical production planning method for job shop subject to machine failures and parts scrapping is studied.This study gives the necessary condition that the planned job quota for a standard production period must satisfy.The capacity requirements for each workcenter accomplishing all of its production quotas in one standard production period are also discussed.The paper proposes an approximate method for estimating the due date lead time.Experiments demonstrate the validity of the estimation method.Therefore,it can be used in production practice.