Alias effect in satellite altimetry has been a topic of active research in recent years, as a result of a growing recognition of its remarkable potential consequences. So far, alias problems have been addressed in both time and space domains, but in the latter case only on the horizontal scales. In this study, we examine the impacts of alias effect on the amplitude of sea surface height measurements, which were previously of little concern. Three statistics are proposed to diagnose the resolvable amplitude or energy with respect to the original period, initial phase and data duration in the context of aliasing. The results obtained show clear evidence to support the argument that alias effect on amplitude is a common feature in altimeter sea surface height measurements, and is as important as other alias consequences.