The utility model provides a steel strand pre-tightening device, belongs to the technical field of hoisting machinery installing, and is particularly applied to installing and constructing of steel strand type hydraulic lifting equipment. The device is of a symmetric structure, and comprises a support block, a compression mechanism and a strand tightening mechanism, and the compression mechanism and the strand tightening mechanism are respectively connected with the support block. The steel strand pre-tightening device is installed on the upper part of the steel strand type hydraulic lifting equipment, so that the uniform pre-tightening force on all steel strands on the same hydraulic lifting equipment can be ensured; when multiple pieces of hydraulic lifting equipment simultaneously adopt the steel strand pre-tightening devices for pre-tightening, the load balance of a stressed system can be ensured. The flexible function of the hydraulic lifting equipment jack is utilized, manual pre-tightening is not needed, steel strands on the single jack are pre-tightened for one time, and meanwhile, the device can be used to carry out cluster pre-tightening, the pre-tightening efficiency is improved, the labor strength is lowered, and the pre-tightening quality is ensured.