Magnetic drug delivery system (MDDS) is a key technology effects in the medical applications, and also the magnetic force control is a very important issue in MDDS. In general, the high magnetic field along the axial direction and high magnetic field gradient along the longitudinal direction are very useful for MDDS. So, we proposed the new magnetic force control system consists of superconducting magnet, high temperature superconductors (HTS) bulks or tapes and irons. In this system, the shielding currents in HTS bulks and tapes due to the diamagnetism of the superconductor generate the magnetic field with same direction of external magnetic field, and we can control the magnetic field gradient along the longitudinal direction by the arrangement of the superconductors and irons. In this study, the stacked GdBCO tapes were used in experiments and electromagnetic analysis based on finite-element method was carried out to optimize the arrangement of the superconductors and the irons. It was confirmed the control of magnetic field gradient along the longitudinal direction was possible by arranging the HTS bulks, tapes and irons on the superconducting magnet. In analysis, the magnetic field of 164.6 mT and field gradient of 1.89 T/m were obtained.