Abstract: Using the dynamic causal model (DCM), the functional magnetic resonance imaging (fMRI) data of right-hand motor execution (ME) and motor imagery (MI) are analyzed to detect the dynamic networks between contralateral primary motor cortex (M1) and bilateral supplementary motor area (SMA) in the present study. The results show the dominant function of left SMA during both ME and MI, and the suppressive influence of left SMA on left M1 during MI. Furthermore, the difference of the dynamic networks during ME and MI is analyzed and the results suggest the alteration of the influence of the stimulus on the activated regions during ME and MI, implying the transformation of the neural mechanism in dynamic networks of ME and MI.