The plantar orthosis system based on CADCAM system has very important practical value in the treatment of foot diseases. In order to effectively alleviate the growing incidence of foot disease in our country, the author gives an overview of the related theories of CADCAM system in this study. Then the author designs the foot orthosis based on computer system and applies it to practical during the treatment of plantar diseases. The results show that the CADCAM which is based plantar orthotic system can effectively treat patients with foot diseases by comparing to the traditional foot disease treatment. The purpose of this study is to provide a reference for the improvement of related technologies in the treatment of foot diseases.