Abstract: Different frequency oscillations caused by the large-scale applications of the voltage source converters（VSCs） in current control timescale have brought great effects to the voltage amplitude/frequency dynamics of the power systems. However, the existing studies did not recognize that the essence of the system dynamic above is the modulating process of the internal voltage amplitude/frequency. Besides, relevant studies based on the amplitude/frequency modulation to analyze the system dynamic induced by VSC in current control timescale are still lacking. Thus, this paper proposed a method based on the amplitude/frequency modulation for the dynamic analysis of VSC-dominated power systems in current control timescale. Firstly, this paper introduced the basic structure and the amplitude/frequency modulation essence of multi-VSC system. The mistakes of cognizing the essence of VSC’s dynamic as the harmonic dynamic were also clarified. Then, the basic challenges of the primitive mathematical models and their linearization of both VSC and the power network were discussed with time simulations. Eventually, the proposed method above can be applied to intuitively analyze the causal cycle process of the amplitude/frequency modulation and the active/reactive power modulation, which can also be used to uniformly summarize the effects of the diverse devices and the power network on the amplitude/frequency dynamic concerned by the power systems.