The invention provides an overhead working platform for power transmission lines, which comprises a platform main body, folding plates and folding plate folding slideway locking structures, and is characterized in that the platform main body is of a hanging basket structure; the folding plates are respectively arranged at two opposite sides of the platform main body, one end of each folding plate is connected with the platform main body through the folding plate folding slideway locking structure; each folding plate folding slideway locking structure comprises a folding plate moving slot structure, folding plate moving shaft connecting plates and locking shafts, wherein the folding plate moving shaft connecting plates are arranged at two sides of the folding plate, the folding plate moving shaft connecting plates slide along the folding plate moving slot structure so as to enable the folding plate to rotate by taking the end connected with the platform main body as a shaft; and the locking shafts are arranged at two ends of the folding plate moving slot structure and used for buckling the folding plate moving shaft connecting plates. The overhead working platform solves a problem that the space of the platform main body is small, facilitates transportation of the platform and improves the working efficiency of operators.