Aiming at the single batch-processing machine with non-identical job sizes, an ant colony algorithm is proposed to make span. First, artificial ants are used to search the paths in the model to get a sequence of jobs and then heuristics are adopted to assign the jobs into batches, which form solutions of the problem. In the simulation part, different levels of instances are taken and the results show that the proposed algorithm is efficient in solving the problem. The scheduling of multi-machine with non-identical job sizes deserves further research in the future.