The invention discloses a numerical control swinging experimental device of the overhead transmission line. A support (1) is connected with a support ball linear guide pair (2) and support tooth bars (4), the support ball linear guide pair (2) is connected with connection boards (6) which are connected with first motor speed reducers (5) respectively, each first motor speed reducer (5) is connected with a vertical gear (14) which is engaged with the support tooth bar (4), a crossbeam (7) is connected with a crossbeam tooth bar (8) and a crossbeam ball linear guide pair (9), the crossbeam ball linear guide pair (9) is connected with a slide plate (11) which is connected with a second motor speed reducer (10), the second motor speed reducer (10) is connected with a horizontal gear (15) which is engaged with the crossbeam tooth bar (8), a first cable tow chain (3) is connected to the support (1) and the crossbeam (7), and a second cable tow chain (12) is connected with the slide plate (11) which is connected with the crossbeam and a lead clamp (16). The numerical control swinging experimental device is simple and practical in structure, high in carrying capacity, speed, positioning precision and reliability, smooth in transmission, and not limited by wind power in the natural environment.