This paper explores the influence of the voltage and current feedforward control on the stability of the grid-forming inverters. By means of the small-signal model, it is revealed that inappropriate feedforward coefficients indeed challenge the system stability at both low and high frequencies. Furthermore, the exploration has also indicated that the grid impedance affects the stable region of voltage and current feedforward terms to a large extent, while the operational points have negligible impact. Simulation results verify the correctness of the analysis.