A numerical model has been proposed to analyze the stability margin and quench characteristics of the cable-inconduit NbTi conductors for the KSTAR-PF magnets. The dependence of the thermal, hydraulic and electrical properties on the external thermal disturbance was investigated. The algorithm of the program is based on the finite volume method which adopts space discretization and time intergration by multi-step Runge-Kutta method to obtain stable numerical solutions. It was confirmed that the disturbance duration can influence the conductor stability and limiting current.