Based on the survey of customer satisfaction, the authors found existing problems in inspection process of the food safety monitoring laboratory A (including the whole process from receiving samples to issue of inspection report), and determined solutions using flow chart supplied by sig sigma (6σ) theory. Through comparing overall effect before and after improvement of the inspection process, it is proved that 6σ management theory is a new effective management tool for eliminating errors, simplifying process, and meeting requirements of customers to the maximal extent.