Abstract: Using the TCA2003 surveying robot of leica,collected the surface movement deformation data of a mine working face which is in the process of mining in the west mountain district under the small time scale,researched and analysed the measured data,we get a conclusion that under the small time scale the ground surface sinking of subsidence area in mountain region is an irregular rapid changes.It is changed with nonlinear volatility,which is more intense when the selecting time scale is smaller.The instantaneous velocity is huge.It may leads to the destruction of buildings instantly.Precautions should be paid attention to in mining process.The dynamic subsidence velocity curve of surface points have a statistical fractal characteristics with the model of "z" type.