This project studies dispatching rule techniques in machining section of the case study in which concerns with a job shop manufacturing system. Presently, the planner plans the schedule which does not follow any scientific method for scheduling purposes. The problems are resulted into some jobs overdue on the schedules and over load on some machines. The objectives of this study are to minimize throughput times and reduce a number of tardiness jobs. Dispatching rules technique and simulation model is applied to solve and find a good solution on job shop scheduling problem in case study. The results show that the effectiveness of dispatching rules which considered in term of throughput times and utilizations. The SPT rule is given the best result compare with other rules and in term of the number of tardiness job the EDD rule is suitable method which can reduce in the jobs overdue problem.