The invention provides a sheave pulley adjusting based tension balancing system and method for a lifting steel wire rope of a vertical shaft, and aims at balancing the tension among a plurality of lifting steel wire ropes of a sheave pulley in an ultra-deep vertical shaft lifting system. The device comprises a front platform, a rear platform, an upper platform, a sheave pulley set, steel wire ropes and roller devices, wherein the front platform and the rear platform can move up and down; the upper platform is fixedly mounted; the sheave pulley set is mounted on the upper platform; the steel wire ropes are arranged round the pulley set; the roller devices are used for adjusting the tension balance of the steel wire ropes; in case of unbalanced tension of the lifting steel wire rope on each sheave pulley, the roller device is driven to act by the active running of a motor or through the passive effect caused by the tension difference of the lifting steel wire ropes according to the releasing or compressing state of a gate on the corresponding roller device, thus the steel wire rope on a corresponding roller can be upwards coiled or downwards uncoiled, and the corresponding platform or shaft is driven to move upwards or downwards, and as a result, the corresponding sheave pulley can be driven to move up and down to balance the tension among the steel wire ropes. The system is simple in structure, convenient to operate, and high in reliability; the problem of tension balancing of the plurality of steel wire ropes can be effectively reduced.