The invention provides a live line work mechanical arm autonomous obstacle avoidance path searching method based on movement primitive libraries. A complete mechanical arm kinematic model and a mechanical arm simplified kinematic model are built, and a mechanical arm working environment is built; the movement primitive libraries are designed in a classified mode, and corresponding movement primitives are designed for the various libraries to serve as library members; distance calculation functions between a mechanical arm and a target point and between the mechanical arm and an obstacle are built in a classified mode, and the danger area threshold value and the target point arriving precision threshold value are set; a heuristic function hd(x) in the Cartesian space and a heuristic function hc(x) in the articulate space, and a heuristic rule are created, and heuristic searching is achieved; and the current pose and the expected pose of the mechanical arm and the Cartesian space distance of the obstacle are calculated, and a path is planned according to the set judgment condition. Mechanical arm operation scene information can be built rapidly and precisely, it is guaranteed that the obstacle avoidance path searching result has suboptimality and completeness, the path can be planned rapidly under the premise of meeting the kinematic constraint, and the stationarity of the mechanical arm movement process is guaranteed.