Objective To seek more direct evidence of the role of the posterior parietal cortex (PPC) in controlling visuospatial attention.Methods Forty healthy subjects took the Attention Network Test following continuous theta burst stimulation (cTBS) applied over the left or right PPC or sham stimulation.The Attention Network Test measures the alerting,orienting and executive control components of visual attention separately.Results Subjects responded to spatial cues significantly slower after cTBS.Alerting and orienting showed deficits after cTBS over the right PPC.cTBS over the left PPC resulted in significant improvements in alerting,but not in the orienting.Furthermore,there were significant differences in the alerting and orienting indices between cTBS over the left and right PPC,but not in the executive control index.Conclusions The results suggest that the right PPC is associated with spatial orienting and the alerting function.The findings supported the theory of inter-hemispheric competition for visuospatial attention.Visuospatial attention bias might be selectively modulated through cTBS.