Abstract: By experiment and Random Coupling Model（RCM）, the statistic characteristics of induced voltages at key points in computer box cavity are studied. The calculating method and application diagram of RCM is given. Scattering coefficients, the statistic characteristics of normalized scattering coefficient and normalized impedance coefficient are researched by experiment and theory. It is shown that the experiment results generally agree with the theoretical results in trend. Application of RCM is preliminarily discussed. Applicability of analysis and forecast on systemic electromagnetic environment effects based on RCM is validated. Especially, the RCM is applicable to investigation on electromagnetic compatibility, effects and assessment for the large scale nonparallel surface electronic systems.