None Practical technique that aids in scheduling largescaled producting task has been reported. The main reason is that there is lacking of concise,ping pointing arithmetic model that meets the needs of the real world practice, In addition, up to thousands tasks cannot be ordered automatically to the event number in the network diagram via the interior logic relationship and remained unchanged in the rnaking and revising the whole plan. It is the very topic that will solve the problem, TLZ model and the implementation, in this paper, Practice in more than two years has proven the correctness of the model and the arithmetic as well as the efficiency of the program. In January this year,TLZ was evaluated by the provincial experts who consider that it is valuable and widely used in the scholarly work.