The present study used event-related potentials (ERPs) to examine the time-course and neural mechanisms of processing metaphorical and literal expressions. The stimuli materials were two-word expressions consisting of literal semantic relations, evoked metaphor, or derived metaphor. Participants had to make a judgment whether each word pair conveyed a meaningful expression or not. Meanwhile, ERPs components of the second word were recorded and off-line analyzed. The results revealed that on the N400 time window, amplitudes in a graded manner increasing from derived metaphor to literal expressions and evoked metaphor. On the P600 time window, metaphorical expressions elicited more positive amplitudes than literal expressions but no difference between these two types of metaphor. Moreover, N400 s elicited by different experimental conditions showed no significant hemisphere difference, however, evoked metaphor elicited more negative amplitudes than literal expressions in the right hemisphere. The results support the parallel hypothesis of metaphor comprehension. Metaphorical nature and processing stages may determine whether the right hemisphere is involved in metaphor comprehension and the degree of its involvement.