Wayelet entropy (WE), a new complexity measurc of electroencephalographic (EEG) signal, was investigated under two physiological states for a better understanding of brain dynamics In the quantitative analysis, higher mean WE values of 16-channel EEGs under eyes open state imply higher degrees of EEG complexity compared with their counterparts under eyes closed state which exhibits that morc complex process will OCCUr even when a very simple neural Information processing happens (e. g., eyes open) In the qualitative analysis, blocked alpha rhythms were observed under eyes open state over posterior (particularly occipital) areas via the time-frequency, the time-space, and the time-frequency-space variability of relative wavelet intensity (RWI); and the evolution of delta rhythm is against the change of the WE under both two states，which suggests stronger delta activities ale corresponding with lower degrees of EEG complexity (i.e., lower WE).