It is one of the effective way to apply JIT (just in time) mode in the management of discrete job shop to improve the productivity of job shop. A kind of JIT management mode for discrete job shop is proposed in this paper. The machining tools such as cutters and frocks are distributed with materials in JIT mode, so that the inventory of machining tools is reduced, and productivity is improved. The process of distribution plan under this mode is studied. The JIT distribution management information system is developed based on the proposed studies, and is applied in a traditional machining job shop with satisfactory result.