Numerous studies provide evidence that motor skill acquisition is associated with dynamic changes in cortical and subcortical regions. Athletes are a professional population who are engaged in extensive motor training for long periods. However, the neural substrates of extreme level motor performance have not been clarified. We used kinesthetic imagery task to induce the mental representation of sport expert's extraordinary performance in view of the shared substrates of executing movement and motor imagery. For the first time, we compared, through functional magnetic resonance imaging (fMRI), the pattern of cerebral activations in 12 professional divers and 12 normal people without extensive training, during imagery of professional skills and imagery of simple motor skills. The sport experts showed significant activation in the parahippocampus during imagery of professional skills relative to the novices, which might reflect the representation adapted to experience-related motor tasks. No significant difference was found between experts and novices when they imagined simple motor skills. These results indicated the experts might utilize their kinesthetic imagery more efficiently than novices, but only for the activity in which they had expertise. The sport experts also demonstrated more focused activation patterns in prefrontal areas in both of imagery tasks, which may be relevant to higher order of motor control during motor imagery. Moreover, this study suggested that the brains of sport experts could be regarded as the ideal subjects to explore the relationship between cerebral plasticity and learning of complex motor skills.