Noise reduction in a shop floor is one of the important parts of green manufacturing. In a shop floor, machine tools are the main noise sources in a shop floor. A new approach is discovered by investigation that the noise can be obviously reduced in a shop floor by optimizing the scheduling between work pieces and machine tools. Based on the discovery, a new method of noise reduction is proposed. A noise reduction scheduling model in a shop floor is established, and the application of the model is also discussed. A case is studied, which shows that the method and model are practical.