The underground water system in mining area is a nonlinear evolutionary system,and the variation of the groundwater level universally is also a non-integrable process.With the mineral extraction,the evolutionary process of the groundwater level will entry chaotic condition via particular path.This article analyses the time series data from the water level observation on the first long-term hydrogeologic observation drill of "Ordovician limestone" in Yangzhuang coal mine.Based on the phase space reconstruction technology provided by the Pacard and Takens,first the delay time is determined by the self-correlation function and the optimal inserted dimension is calculated,the maximal Lyapunov index is took out from the single variation by using method provided by Wolf.According to the results,it is found that the time series of the groundwater level is of chaotic feature.On the base of the above,the six-step prediction of the groundwater is done by the local method of chaotic time series.The consequence is that chaotic time series prediction is more accurate in the prediction of chaotic series.