The invention relates to a parallel controllable drilling robot mechanism, comprising a revolving platform, a rack, a movable platform, a central branch chain provided with a closed-loop subchain and a controllable adjusting branch chain, The rack is arranged on the revolving platform, the revolving platform can be arranged on various travelling devices or fixing devices, and the rack is provided with five servo motors. The back of the movable platform is provided with five ball pairs, and a flange plate on the movable platform is used for mounting different devices such as a drilling gun, a spraying device, a welding gun and the like. All the servo motors of the mechanism are arranged on the rack, the motion inertia of the mechanism is small, the dynamic performances are good, and the mechanism is convenient to dismount, has strong expansion capability and can meet the operation requirements of high-precision large-load drilling and the like.