Inhibition of Return refers to the delayed response times to targets presented at the previously attended locations or objects as compared to the novel ones. It has been considered as a mechanism that biases attention towards novel locations in the visual field so as to facilitate visual searching efficiency. Since mid-1990’s, more and more studies in this field have focused on exploring the capacity of inhibition of return, i.e., how many previously cued locations can be inhibited by this mechanism. This article provides an overall review on the studies of inhibition of return at multiple locations with two major research paradigms -- the sequential cueing and simultaneous cueing paradigms. It summarizes the achievements as well as the characteristics and problems in this field and points out the possible direction for future research