Abstract: It is difficult to implement treatment in slim hole wells because of the small internal diameter of casing, big limitation on tool selection and complexity and diversity of falling objects. Aimed at this, a series of fishing tools in slim hole wells was developed including oil pipe hoop back off sub, prevent channeling external hook and three adjustable ball overshot. The structure, operational principle, technique characteristics and field application cases of these tools were introduced in this paper. The application of these tools greatly enhanced the salvage success rate solved difficult problem of implement treatment in slim hole wells, which provide some technical reference for fishing in slim hole wells.