The invention discloses a spatial multi-degree-of-freedom surgery assisting arm mechanism, which comprises an arm bracket, a touch hand assembly and a motion component which is connected between the touch hand assembly and the arm bracket and is used for conducting three-dimensional direction adjustment on the touch hand assembly, wherein the touch hand assembly comprises a touch hand mounting tray and a plurality of touch hands which are fixedly arranged on the touch hand mounting tray; each of the touch hands is formed by hinging a plurality of touch hand sub-sections, and an elastic limiting piece, which is used for limiting a relative rotating angle between every two adjacent touch hand sub-sections, is arranged between the every two adjacent touch hand sub-sections; the motion component comprises a horizontal direction adjusting unit and a vertical direction adjusting unit; and the positions of both the horizontal direction adjusting unit and the vertical direction adjusting unit are adjusted by virtue of a worm-gear pair structure. The arm mechanism disclosed by the invention is simple and efficient to operate and low in cost, and is suitable for assisting doctors in various surgical operations.