Abstract: In order to solve the difficultyt of the water inrush accidents from the seam floor, the electric resistivity method to dynamic monitoring and measuring, site observation and theoretical analysis method were applied to study the stress distribution law of the coal mining face floor and the floor failure law.A relationship betwee n the electric resistivity variation and the mining affected to the disturbance of the coal mining face floor was obtained.Taking the monitoring and measuring information of the floor electric resistivity during the mining process of No.4309 coal mining face in Tangkou Mine as the basic data, the dynamic variation law of the floor disturban ce in the coal mining face was obtained.The results showed that the mining disturbance would have the compression expansion recovery dynamic variation features tim ely and would have the features to steadily reduce with the floor depth increased.