Abstract: Well 001-3 in Longgang field is completed with the total depth of 6643.89 m. During the liner cementing process, bit sticking is caused by the cement setting, and the length of the fish is 1847.6m. After analyzing the case, it was believed that only long section milling treatment could trip the fish. To ensure the safety of the mill pipe and ?177.8 mm casing, the difficulties of the treatment were analyzed and the solving plan was optimized, which was to modify the mill ring to satisfy with the ability of milling iron and cement but not damaging the casing. Through managing the rotating torque, the damage of milling the curved fish to the mill ring was decreased. The tripping method for the irregularly shaped fish after milling treatment was found. The treatment ensured the conduction of milling and tripping for the cementing section with the depth of 3896.79~4733.40 m, and it made no damage to the mill pipe or casing. The treatment supplies a valuable case to the same type wells.