The length without cable has a significant effect on the mechanical properties of the bridge, and the appropriate length without cable can optimize the force of the overall structure of the bridge, so the length selection is particularly important in the bridge design. A single-tower cable-stayed bridge with a span diameter of (196 + 101 + 62) m in the western Hunan is taken as the engineering background, and the finite element analysis software Midas civil is used to establish an analysis model, and the length without cable at the root of the tower and the end of the beam is analyzed by single factor. The results show that the change of the length without cable at the root of the tower and the end of the beam has a significant effect on the deflection of the main beam of the main span and the deflection of the main beam of the side span, but has little influence on the maximum tensile force of the stay cable. The results can provide a certain reference for overall design of cable-stayed bridge.