The purpose of this thesis is to design an innovative sickbed for the paralyzed patients. One goal of the sickbed is to avoid the occurrence of pressure ulcers. The other one is to tune the tensions of patient¡¦s muscles. To analyze the muscle tension, a simplified model for human body was proposed. This model divided the human body into 5 blocks when ignoring the arms and hands. It described the geometric relationships between the blocks and muscles under different body postures and external supports from the design sickbed. It was noted that the number of unknowns of the model was larger than the number of equations derived from the equilibrium conditions. An optimization method, which was to obtain a desired distribution of muscle tensions, was adopted to find the solutions for the unknowns. Among the possible supporting states, which included the body postures and supporting locations, the ones that met the desired tension distribution were searched. Then, the technique of Graph theory was used to obtain a set of supporting states that could avoid the occurrence of pressure ulcers. Finally, a preliminary design of the sickbed structure was discussed. If the relaxed condition of muscles was desired, the simulation study indicated that large number of supporting states could meet the purpose. That means there exist many body postures or supporting locations allowing the muscles of body in the relaxed condition. This feature allows one to choose a set of supporting states that two consecutive states own different supporting locations and prevents any spot of body from continuous loading. Such a supporting scheme should minimize the occurrence of pressure ulcers.