High temperature superconductor (HTS) magnetic levitation is proposed to be applied in the micro thrust (mN level) measurement to achieve a fully suspending measuring method for electric propulsion devices, which can get rid of all connecting interferences and lead to higher precision. Levitation friction loss is still the main problem limiting the response of HTS levitation to small tangent momentum. To investigate the friction loss characteristics at low speeds, we designed and established a set of single permanent magnet/superconductor levitating rotation setup. The initial rotation angular momentum of the magnet is given by a small impact pendulum with high accuracy, and the swinging angle of the magnet is recorded by a digital image processing method depending on a CCD camera. Through the setup, the swinging rotation of the magnet is observed and the low friction loss is analyzed. The relation between the swinging rotation and field cooling heights is also discussed. The research is helpful of understanding the friction loss mechanism and mechanical properties of HTS levitation under tiny disturbances. It provides important technical support to develop the micro thrust measuring device depending on HTS levitation.