Characteristic of subsidence is significant different in different temporal scale. Subsidence of the active points on a first mining workface was measured every other minute using several methods, such as Level, Total Station, and GPS. Based on the data, several conclusions are put forward. They are:(1) Under a certain geological and mining condition, subsidence can't happen suddenly. (2) In small time scale, subsidence velocity in both of the magnitude and direction varys with strong fluctuation which exacerbates with the decrease of time scale. (3) Extremal velocity of subsidence follows negative exponential function with timel scale. The study discloses the complexity of subsidence and is important to the study on the building damage in subsidence area.