Abstract: A new semi-analytical model of torque and rotational angle relationship for multi-bundled conductors is proposed. It is suitable for the calculation of large-span large-rotational angles and twisting scenarios. The model considers the vertical and horizontal displacement of the spacer and the tension variation of the sub-wire during the torsion process. It also considers the nonlinear distribution of the rotational angle along the span length. The calculation results are compared with the finite element method and experimental results which show that the geometric nonlinearity of multi-bundled conductors has a significant effect on the recovery torque. The semi-analytical model has a high calculation accuracy in both small and large rotational angle scenarios and can provide a basis for determining whether the conductors are twisted. The relationship between T-θ curves and the number of spacers is analyzed in detail to investigate the effectiveness of increasing the number of spacers in suppressing the twisting. It is found that only a small increase in the number of spacers can ensure the safety by the fact that the stiffness remains positive and the conductor can be restored by itself even if it is twisted by 180°. For the case of extremely large torque, more spacers are needed to maintain a positive torsional stiffness when it is twisted by 360°, which means that the conductor still has the ability to restore after twisting occurs.