Abstract: A new special electromagnetic fishing device for large diameter wells is developed. Based on the structural design of the device, the characteristics, key functions and research significance of its electromagnet module, removable pulley module, resistance reduction and flow diversion module, optional fishing basket module, water cooling technology and waterproof technology are discussed, and its application test is carried out. The results show that the electromagnetic fishing device developed for large diameter wells operates stably and reliably with high success rate of fishing and strong inter-well commonality, which can meet the needs of handling metal falling accidents in large diameter drilling construction.