The invention relates to the technical field of cable processing, in particular to a manual tension adjusting device of a tension pay-off reel. The manual tension adjusting device comprises a tensionadjusting screw rod which is horizontally arranged, and the tension adjusting screw rod is connected with a supporting rib plate through a spring. One end of the supporting rib plate is connected witha lower positioning block, and the other end of the supporting rib plate is connected with an upper positioning block. The upper positioning block is connected with a friction block, and the frictionblock is in contact with the bottom of a friction plate. The manual tension adjusting device can adjust the friction force borne by the friction plate in real time, and the position of the tension adjusting screw rod is horizontally moved, so that the spring generates pull force or push force on the supporting rib plate; the upper end of the supporting rib plate moves the friction block upwards or downwards, so that the friction force between the friction block and the friction plate is controlled; and the rotating speed of the friction plate is controlled in sequence, so that tension adjustment is realized.