A steering control method of a motor-driven power steering system, the steering control method comprising: setting, by a controller, a virtual steering model (VM) including a torsion bar provided between a steering wheel and a rack gear ; inducing, by the controller (CLR), a state equation for the virtual steering model (VM), the state equation representing momentum of the steering wheel , the torsion bar, and the rack gear as state variables of the state equation; determining, by the controller (CLR), a target steering torque (Tq_ref) acting in the torsion bar through numerical integration of the state equation; and feedback-controlling, by the controller (CLR), a steering motor control amount of the motor-driven power steering system to bring a steering torque of the motor-driven power steering system into agreement with the target steering torque, wherein, in the virtual steering model (VM), a steering angle speed (ωsw) and a rack force (Frack) are applied as input variables of the virtual steering model (VM); inertia of a steering wheel , rigidity of the torsion bar, a damping constant of the torsion bar (Bt), a column friction of the torsion bar, a pinion radius (Rp), and weight (Mr) of the rack gear are applied as system characteristic parameters of the virtual steering model (VM); and the target steering torque (Tq_ref) determined by relations of the input variables of the virtual steering model (VM) with the system characteristic parameters of the virtual steering model (VM) is applied as an output variable of the virtual steering model, wherein the state equation for the virtual steering model (VM) is induced by use of a bond graph, and the state equation is induced by setting twisting displacement of the torsion bar (q5), rack gear momentum, steering wheel momentum, and rack gear displacement as the state variables of the state equation. setting, by a controller, a virtual steering model (VM) including a torsion bar provided between a steering wheel and a rack gear ; inducing, by the controller (CLR), a state equation for the virtual steering model (VM), the state equation representing momentum of the steering wheel , the torsion bar, and the rack gear as state variables of the state equation; determining, by the controller (CLR), a target steering torque (Tq_ref) acting in the torsion bar through numerical integration of the state equation; and feedback-controlling, by the controller (CLR), a steering motor control amount of the motor-driven power steering system to bring a steering torque of the motor-driven power steering system into agreement with the target steering torque, wherein, in the virtual steering model (VM), a steering angle speed (ωsw) and a rack force (Frack) are applied as input variables of the virtual steering model (VM); inertia of a steering wheel , rigidity of the torsion bar, a damping constant of the torsion bar (Bt), a column friction of the torsion bar, a pinion radius (Rp), and weight (Mr) of the rack gear are applied as system characteristic parameters of the virtual steering model (VM); and the target steering torque (Tq_ref) determined by relations of the input variables of the virtual steering model (VM) with the system characteristic parameters of the virtual steering model (VM) is applied as an output variable of the virtual steering model, wherein the state equation for the virtual steering model (VM) is induced by use of a bond graph, and the state equation is induced by setting twisting displacement of the torsion bar (q5), rack gear momentum, steering wheel momentum, and rack gear displacement as the state variables of the state equation. <EOS>