Abstract: In wafer fabrication system, the performance measures of batch processing machine’s schedule have significant impact on plant performance because these machines have time consuming feature. Two phases, batches forming and batches scheduling, are needed to schedule batch machines. The difficulties lie in the former phase because of the dynamic arriving time of jobs. A hybrid ant colony optimization (ACO) algorithm was proposed, which batches the jobs by using the global and parallel searching mechanism of ACO, and schedules these batches by BATC algorithm.With respect to a due datebased objective (minimizing total weighted tardiness), the proposed algorithm was applied to schedule parallel batch process machine with incompatible job families. The performance of the hybridACO algorithm was evaluated and compared with that of other approach through simulations, and the results show that the proposed algorithm can generate quite effective and practical schedule.