Abstract: Based on the oilwell feature to reflect earthquakes. we have studied the mechanism of oilwell dynamic anomaly formation. It is thought that the spacial distribution of sensitive wells to renect earthquakes is controlled by the tectonic condition of stress assembling especcally in the cross section offault, turning point and fault belt. This is the same as the other fluid observation items. It is proposedfor the first time the three force processes of oil well dynamic procursor anomaly formation (they arerock soil mechanics, water dynamic mechanics, and gas dynamic mechannics) and that the view of pointof 2 sorts of special magnifying functions (radius variance and gas expansion) of oil wells. Inner forcecauses of positive anomaly of oil well dynamic state are interpreted.