Abstract: Rod pump drainage is the main technology of land and sea oil and gas well production， but buried pump and stuck pump often happen. Based on the idea of switching between operations without moving pipe string， a downhole circulation opening device is developed. The downhole circulation opening device adopts full mechanical structure design， which can adapt to the complex production and operation conditions of oil and gas wells more widely. The sliding sleeve rotating mechanism is used to realize the switching between the opening and closing of the wellbore space， and the column locking mechanism is used to realize the purpose of sealing the well bottom. The total head loss of 0.818m under extreme working conditions is small， indicating that the flow channel is smooth and the structure is reasonable.

Key words: mechanical pumping of oil and gas wells, downhole tool, circulation opening device, sliding sleeve rotating mechanism