Evaluating trunk control ability is significant in guiding patients towards proper functional training. Most existing devices have only a singular assessment function, resulting in prolonged and asynchronous assessments. Devices with multi-dimensional assessment capabilities may address these limitations. This study utilizes a robotic brace, RoboBDsys-II, to assess the trunk ability of individuals with spinal disorders and to validate its effectiveness. The device can simultaneously collect kinematic, kinetic, and center of pressure data, reducing the assessment time and enabling the simultaneous assessment. The force platform is designed to measure the center of pressure and the force control of the parallel module is developed for the coronal movement assessment. Four patients with spinal cord injury participated in the study to assess their trunk range of motion and muscle strength. Results demonstrate that the trunk range of motion determines the center of pressure metrics in lateral bending experiments. Furthermore, RoboBDsys-II exhibits excellent test-retest reliability in lateral bending experiments and can reveal the muscle strength differences in different directions. The system has potential advantage in the trunk ability assessment.