The invention discloses a rope fixing device used for a spacecraft mechanism and capable of being dismounted and mounted repeatedly. The rope fixing device is constituted by a fixing bottom plate, a rope mounting block, a pressing lining, a rope and a rope mounting block screw fastening piece. The lower bottom face of the rope mounting block can be dismounted from and mounted on the fixing bottomplate repeatedly through screws. A rope mounting groove is machined in the rope mounting block and is in an L shape. One end of the rope is connected with a rope body through the pressing lining to form a closed ring, and the rope mounting block is sleeved with the closed ring which is clamped into the rope mounting groove. Through the rope fixing device, the rope in the spacecraft mechanism can be dismounted, mounted and fixed repeatedly, during dismounting and mounting every time, a hoop at the tail end of the rope does not need to be pressed repeatedly, the rope also does not need to be cut, it is ensured that the length of the rope is not changed, and thus, manufacturability and reliability of rope fixing, dismounting and mounting are achieved.