In this thesis, an 8-link mechanism was designed to simulate real horse walking and running leg. The 8-link type has been decided first, than the solution plane method has been used to the linkage synthesis. A computer software has been developed to solve the given loop equations. This software can give the profile of the mechanism and the information of the link length and the moving curve of the decided touch-ground point quickly. Several 8-link mechanisms were presented according to the designer’s choice. The results show that this method as well as software is able to develop complicate 8-link mechanism freely and correctly. Key word: Bio-mimetic, Linkage mechanism, Computer-aid mechanism design