Back pain is one of the major health issues worldwide and carrying a heavy backpack has been identified as one of the primary causes of back pain. To curb the prevalence of back pain, the recommended safe load limit of a backpack weight is 10-15% of body weight (BW) as exceeding the load limit poses the risk of spinal deformities and back pain. We hypothesize that in addition to the backpack weight, the position of the backpack (the vertical load position and the horizontal distance between the spine and the center of mass (COM) of the backpack,) plays a significant role in determining the load on the spine. In this study, we have developed a 3-dimensional (3D) finite element (FE) based model of three major parts (Cervical, Thoracic, and Lumbar) of the spine and analyze von Mises stress distribution and trunk forward lean angle at different loading conditions.