Abstract: A high temperature superconducting (HTS) magnetically levitated testbed has been developed for the steady thrust measurement of miniature ion electrospray thruster. The structure of the testbed mainly consists of an HTS composite bearing, a magnetic shielding plate, an active electromagnetic brake and a laser displacement sensor. The steady thrust is described as a function of the equilibrium angle displacement of the floating frame. Furthermore, the mechanical behaviors of HTS composite bearing were studied via finite element simulation and experiments, which include the load capacity, levitation stiffness and background noise. The results show that the thrust testbed can keep in low noise and have a load capacity up to 4 kg. According to the ignition testing of the electrospray thruster, the thrust force of 25.2 \mu \rmN was measured by the testbed, which is close to the design value of miniature ion electrospray thruster.