The previous research revealed some functional coupling among nodes in model of motor control in human brain, which described nondirectional synchronous actions among these nodes during movement-readiness state. However, causal relationships among these nodes were still lack, which represented some directional interactions among these nodes in movement-readiness state. In the present study, we used functional magnetic resonance imaging (fMRI) and conditional Granger causality (CGC) method to investigate the interactions in model of motor control in movement-readiness state. Our result showed that upper precuneus and cingulate motor area revealed net causal influences with contralateral supplementary motor areas and contralateral caudate nucleus during the left hands movement-readiness state. Moreover, the results of Out-In degrees indicated that bilateral primary sensorimotor areas revealed competitive relationship during left hands movement-readiness.