The invention provides a constant-force installing mechanism for ball-head sliding sleeves, and belongs to the technical field of ball hinge assembling. The constant-force installing mechanism comprises a driving bevel gear, a first driven bevel gear and a second driven bevel gear, a ball-head rod is installed on a ball-head rod support, a locating pin penetrates through an insertion hole of the ball-head rod support and a locating hole of a rod body, the driving bevel gear is coaxially fixed to the left side of a rotating shaft, and a second gear is coaxially fixed to the right side of the rotating shaft; a first gear is coaxially connected with a driving motor, the first gear is meshed with the second gear, and the a first gear shaft and a second gear shaft are coaxially arranged; and the first driven bevel gear is coaxially installed on the first gear shaft, the second driven bevel shaft is coaxially installed on the second gear shaft, the first driven bevel gear and the second driven bevel gear are both meshed with the driving bevel gear, the right end of an upper pressing finger is fixedly bonded to the first gear shaft, and the right end of a lower pressing finger is fixedlybonded to the second gear shaft. According to the constant-force installing mechanism for the ball-head sliding sleeves, constant-force installation of the ball-head sliding sleeves on the two sides is achieved, the structure is reasonable, and the reliability is good.