Abstract: With the needs of geological reservoir development and the steady development of offshore drilling technology, offshore drilling is characterized by multi-target and complex trajectory, and the risk of cable operation increases accordingly. A well in East China Sea was successfully completed in the 8.5 inch well section. In view of the fact that the well is a three-dimensional backtracking well and the borehole trajectory is relatively complex, the open hole electrical logging scheme is optimized: the first acoustic cable logging, the second neutron+density cable logging, and the third piezometric cable logging. During the second neutron+density logging retest data of open hole wireline logging, the instrument was stuck at a depth of 2785 meters and a fish-top depth of 2769 meters. In view of the fact that the downhole instruments have radioactive sources, it is finally determined that the fishing operation is organized by means of the core piercing fishing, and the fish is successfully caught. The instruments are completely and safely pulled out of the well, as well as the radioactive sources. This paper describes in detail the process of instrument jamming and fishing operation, providing reference for the subsequent drilling and completion of the same type or similar wells, and providing reference for similar downhole complex situations in the future.