This paper includes an example of applying Six Sigma to Non-function test process to improve the efficiency and reliability of the Ammunition Stockpile Reliability Program (ASRP). By applying the DMAIC which is one of the Six sigma methods. we found out the vital few and as an improved version : effective redesign of check-sheets, pre-examination of technology, on-the-scene support system. As a result, we could enhance the reliability and reduce manpower and additional expenses.