Finite　element　equations　of　piezoelectric　stack　element　with　electric-mechanical　coupled　effect　are　deduced　using　linear　piezoelectricity　and　Hamilton　Principle.　An　optimal　control　model　of　piezoelectric　smart　truss　which　makes　the　maximum　controlling　nodal　displacements　to　be　minimized　and　subjects　to　strength　of　the　structure　and　characteristic　of　the　actuators　is　established　and　simulated.　In　order　to　overcome　the　deficiencies　of　single　objective,　an　optimal　control　model　which　considers　strength　of　the　structure,　precision　of　the　structures　and　energy　consumption　of　control　contemporarily　is　set.　For　static　indeterminate　truss,　the　maximum　stress　in　the　structure　can　be　decreased,　and　the　maximum　controlling　nodal　displacements　can　be　minimized　simultaneously.