Abstract: According to the geological characteristics and the procedure of long-term water injection in GuDao oilfield, this paper analyze the forming mechanism of big pore path, and it’s performing characteristics in water injection well. Many kinds of water plugging agent were screened and evaluated in the lab., finally determined to choose HD-1 inorganic particle style and LWSD-1 lignin sulfate calcium compound to do it. A detail principal was introduced in choosing well, choosing layer and profile control plugging method. Since 1997, 58 wells were disposal, total increase oil 57383t, decrease water 71361m3, the input-output ratio is 1:2.37.