Quantification of Margins and Uncertainties (QMU) method is a new developed approach for reliability analysis and assessment. In this paper, the technical architecture of system reliability assessment is built on QMU. Firstly, the hierarchy property of Watch List (WL) is researched and the primary steps of setting up WL are provided. Secondly, four ways of establishing performance gate are provided according to the sources and characteristics of performance parameters. Thirdly, two methods of UQ (Quantification of Uncertainties) are presented. QMU can help engineers in recognizing failure modes and solving complex problems in system reliability assessments. It will provide an entirely new design and assessment model for reliability engineers.