The invention discloses an unclamping method and device adopting continuous jarring through spring periodically stretching out and drawing back. According to the unclamping method and device, a valveis arranged in a tubular column, when the pressure of circulating fluid entering the tubular column is larger than the counter-acting force of a spring inside the tubular column and a valve hole is closed, the pressure of the circulating fluid compresses the spring and is converted into compressed elastic
potential energy of the spring, when the compressed elastic
potential energy of the spring isincreased gradually and equal to the pressure of the circulating fluid, the valve hole is opened, the pressure inside the tubular column is unbalanced instantly, the compressed elastic
potential energy of the spring is released instantly and drives a
jar weight inside the tubular column to upwards
impact suddenly, and impacting
kinetic energy is transmitted to the clamping point through the tubular column; after one-time impacting is completed, all components inside the tubular column are reset simultaneously to well prepare for
energy storage impact of the next time, the process is repeated,and periodical repeat jarring is formed till unclamping is achieved. The unclamping method and device can be used for salvage operation of vertical wells and can also be used for unclamping and salvage operation of deviated wells, greatly-displaced wells and
horizontal wells; and during operation, manual resetting operation is not needed, continuous jarring can be achieved till unclamping is achieved, and the unclamping method and device are more efficient and quicker than a conventional technology.