Abstract: Explosive workover technology is a new technique. This technique can be used to repair either casing deformation wells or casing breaking wells, widen the range of workover greatly. The relational expression of diameter enlargement and dosage during explosive enlarging was derived by the way of the energy conservation. The value range of comprehensive influence factor K was given by the simulation test and field testing. The distribution law of pressure wave during explosive enlarging was clarified by numerical simulation. This provided theoretical basis for choosing the method of explosive arrangement anddetonation.