Series KY underground rotaty rig designed and developed according to the conditions of China's underground mines has the modular structure,thus it is mobie in maneuver and easy in operation. This series of rotary rigs were operated in about 10 China's mines ,and the results have shown that this rig is reasonable in structiure,stable in performance ,reliable in working and high in efficiency.Aiming at the problems exposed in operation ,the author puts forward two points of opinion on modification.