The present study used electroencephalography to examine mu rhythm suppression (a putative index of human mirror neuron system activation) at frontal sites (F3, Fz and F4), central sites (C3, Cz and C4), parietal sites (P3, Pz and P4) and occipital sites (O1 and O2), while subjects observed real hand motion (real hand motion condition) and illustrative depictions of hand motion (drawn hand motion condition). Experimental data revealed that mu rhythm suppression was exhibited in the mirror neuron system when subjects observed both real and drawn hand motion. Moreover, the mu rhythm recorded at the F3, Fz, F4, and Pz poles was significantly suppressed while observing both stimulus types, but no obvious mu suppression occurred at the O1, O2 and O3 poles. These results suggest that the observation of drawings of human hand actions can activate the human mirror neuron system. This evidence supports the hypothesis that the mirror neuron system may be involved in intransitively abstract action understanding.