Abstract: In the system test of digital nuclear safety control and instrument (I&C) platform, test requirement analysis is an important activity to identify test features. The concept of product quality attribute was introduced into the process of system test requirement analysis based on the characteristic of nuclear safety I&C platform. A quality attribute classification fitting for nuclear safety I&C platform were presented, and the system test requirement analytic method was established based on the quality attribute and metric. The preliminary application on a certain nuclear safety I&C platform shows that the test requirement analytic method is able to effectually identify crucial test features and to efficiently improve the completeness of platform system test analysis.