Abstract： Objective To investigate the distribution of active pixels when different motor tasks were completed by different lateral upper limb (biceps brachii) and to determine whether there is the the motor task-dependent lateral activity ascendancy of cervical spinal cord. Methods Nine right-handed healthy volunteers received anatomical FRFSE T2WI and gradin-echo-echo-planer imaging functional magnetic resonance imaging(fMRI) with a 1.5T whole body MRI scanner (GE 1.5T Twin speed infinity with excite I1). The volunteers performed two different motor tasks, which were isometric weight bearing task and isometric elbow-flexion, with their bilateral upper limbs. The fMRI data were processed by BOIJ) function package (Function 2.6.61 software package) on the Advantage Workstation. While the signal intensity changes of the active pixels were also analyzed by the SPSS software. Results (1) The concentrated active pixels of spinal cord were found at the spinal segment of C5-C6 under different motor innervations, with a few activity also appearing at the spinal segment of C7-C8. (2) Although the motor task was performed by single upper limb, spinal cord pixels were found on the bilateral sides of the spinal cord in most of all subjects. (3) The fMRI signal intensity change was significantly higher on the side of the cord ipsilateral to the moving upper limb than the contralateral(P < 0. 05). Conclusions The location of spinal cord activation of the two motor tasks has an anatomic correspondence to the segment dominated by spinal cord of the biceps brachii, the main contractor. The motor task-dependent lateral activity ascendancy of cervical spinal cord can be observed.