The invention relates to a method of tension measurement of a steel wire rope in a hoisting system. A sensor is adopted to measure a load force in a horizontal radial direction of a pulley, a load force in a vertical radial direction and a load force in an axial direction, and an included angle between projection on a pulley radial plane of the steel wire rope at a hoisting end and in a vertical radial direction, and tension of the steel wire rope is directly acquired through calculation. The method of the invention is an indirect measurement method, the steel wire rope is not directly contacted, the structure of the steel wire rope is not damaged, the service life of the steel wire rope is ensured, mounting is convenient, calculation is simple, measurement is accurate, the cost is low, the maintenance is simple, the measurement equipment is not in a well, safety of a mining operation is ensured, and the method is particularly applied to tension measurement of the steel wire rope in an ultra deep mine hoist.