Usually the evaluation index of optimal pump operation solution is single. An optimal pump operation model which contained the constraint of start-stop pump unit was developed, and projection pursuit evaluation method for scheme optimization was proposed. The ant colony optimization algorithm was used to calculate the model. The heuristic information and the pheromone trail update method were improved by analyzing characters of the model for better performances. A calculation example for the No.4 Jiangdu pumping station was conducted. The results from ant colony optimization algorithm showed that 29.2% of energy fee could be saved under the designed operation condition, which was compared with the result from dynamic programming with successive approximation algorithm under the same discrete condition, and was better with 2.8% of the result from dynamic programming. The results from ant colony optimization algorithm had less times of the blade adjusting, and shorter operating time of the pumps. Projection pursuit evaluation could give consideration to multiple evaluation indexes. The evaluation result of projection pursuit not only has low electric fee, but also suitable for practical operation, which indicates that ant colony optimization algorithm combined with projection pursuit evaluation method can provide a high application value to the field of optimal operation of pumping stations and related fields.