Ergonomically design is very important for younger body growth healthy. According to the anthropometry which include the differences between adults and teenagers, and the motion of normal behavior and daily domain that influence of sitting situation, which designed for teenagers can get special design that fit for the younger in age stage developmental. Using this virtual simulation technique can detect the design of more product modeling whether accord with human body posture virtual scene lumber curvature, thus obtains the more effectiveness about posture of the human body according to Ergonomically design and back support condition. This method will greatly improve the comfortableness with prolonged sitting, and reduce low-back pain caused by poor chair design. Function of the back support system can affect muscles tension and guard against Adolescent idiopathic scoliosis.