Gyro-magnetic nonlinear transmission line (GNLTL) is a solid state oscillator to generate high power RF electromagnetic pulse, the center frequency of which can be adjusted online. In order to cognize the nonlinear inductor effect on modulated pulse of GNLTL, we established the distributed parameter circuit model of GNLTL, and the influences of initial inductance, saturated inductance and saturated current on the oscillation frequency and rise time of modulated pulse were iteratively analyzed. The analysis results show that the oscillation frequency drops gradually with increase of initial inductance, and there is the fastest rise time at a certain initial inductance. By contrast, the saturated inductance has more effect on the oscillation frequency and rise time of modulated pulse than those of initial inductance. Under the condition of lower saturated inductance, an oscillation pulse with a faster rise time and a higher centre frequency can be obtained. In addition, we notice that the oscillation wave is hard to be modulated whether the saturated current is extremely high or low. In the certain range, the oscillation frequency increases with decrease of saturated current, accordingly, the rise time of modulated pulse is much faster.