Abstract: When a conventional Knthe Tine Function was applied to predit the surace ground dynanic subsiden e caused by the coal ming the surace grnundsubsidence speed and subsidence acceleration refecied were not fited with the actual subsidence aw ofth surface ground.Based on the crcumstance,the paper introduced a new time functon- normal distributed tie function.A detal comparison analysis was conduced on the varation scope and variation law ofth time fucion aue.The normal istributed time functon was provided to the method to determine the surace ground dynamic predictedtime parameers.The time function could be applied to the comparson prediction on the real measured data ofthe suraceground subsidence in a mining area.The stucy showed that the subsidence speed and the subsidence acceleration of the normal distributed time function could be fited with th suface ground dynamic ubsidence law.When ferent accuracy dynamic predction was conducted,the morpholgical parameters of the rational selected function woud be very important. n a mining area.the nomal distibutedtie functioen appltd to the dynamic prediction would be closel fited to the variation lav of the surace ground movement than the prediction with the double parameters Konothe Time Function and the predicted results would be more reliable.