We propose an approach to study the dependence of crystallization on temperature of GeTe-based phase change resistor (PCR) for staircase-shaped voltage pulses. We tune the resistance between the amorphous and crystalline states via varying the width of second subpulse. Then, the crystallized fractions are calculated as a function of the second subpulse widths. Furthermore, the temperature distributions under variable second subpulses are analyzed. At last, the pulse-dependent-recrystallization-temperatures are estimated using experimental and simulation results. We demonstrate that the crystallization of the GeTe-PCR is faster than that of Ge2Sb2Te5-PCR due to the high pulse-dependent-recrystallization-temperature and low activation energy.