In the 6σ-based product quality management system, influencing factors of 5M1E (man, machine, material, method, measure and environment) are the key points to ensure the quality of products reach 6σ level. However, because the traditional quality control methods only focus on the factors of machine, material, method and measure but ignore the factors of man and environment and their relationship on product quality, the 6σ level objective of product quality cannot be implemented well. As such, this study proposes an improving approach for 6σ-based multi-process machining environment whose objective is to build the connection relationship and model among operating environment, workers and product quality. Through adjusting the values of operating environmental parameters, the behaviors of workers on machines can be controlled and the product quality can be improved. This study provides a new solution for 6σ-based product quality control and management.