Marx circuit based on avalanche transistors (ATs) is widely employed to generate high-voltage nanosecond pulses. The introduction of auxiliary triggering topology (ATT) has the potential to significantly reduce the failure rate of ATs. However, investigations into the characteristics of the auxiliary trigger pulse, the circuit operation process, and the switching mechanisms of ATs have primarily relied on theoretical analysis and simulation. Consequently, the effects of stray parameters and other practical factors are often inadequately addressed, thereby limiting the revealable advantages of Marx circuit adopting ATT. In this paper, a multi-stage Marx circuit adopting ATT based on ATs and its simulation model are proposed, and the aforementioned issues are experimentally studied. The results indicate that ATT could utilize the voltage leap generated by the conducted front stages of the Marx circuit to obtain the voltage difference between the base and emitter of ATs, allowing for the formation of auxiliary trigger pulses with distinctive characteristics. Then, the switching mechanisms of ATs in the Marx circuit could be converted from the voltage ramp mode into the base triggering mode. Additionally, the voltage leap enhances the collector-emitter voltage of ATs, so the switching speed of ATs under auxiliary triggering pulses is faster than the traditional base triggering mode. Furthermore, the typical output waveform measured on the 50 Ω load of the 5-stage Marx circuit adopting ATT approximates a double exponential pulse (rising time 2 ns). This work is expected to inspire advancements in circuit optimization, waveform adjustment, and other benefits in applications.