Compared with other stimuli, emotional stimuli usually result in faster and more attention, and present a cognitive processing priority. In the studies of investigating the relation of attention and emotion, emotional materials are observed to attract attention or occupy attention resource, thereby cause attention bias. The current study shows attention bias processing mechanism to emotional information in patients with emotional disorder. Two task-switching indices, Switching Cost and Task Rule Congruency Effect, which represent two distinct sets of processes, have been used so far, which can be measured simultaneously. In addition, this paper provides the necessary basis for emotional modulation. It points out the currently-adopted new technology, such as ERPs and fMRI to study the connection between emotion and attention in the future.