Abstract: To meet the requirements of applications such as extreme ultraviolet (EUV) sources for droplet trains with small diameters, large spacing, and high sphericity, this work proposes a method to generate micron-scale droplet trains by precisely controlling the eccentric collisions of liquid-metal droplets in a two-dimensional plane. The formation of monodisperse satellite droplet trains resulting from eccentric binary collisions of Ga–In–Sn alloy droplets is systematically investigated. A critical eccentricity model applicable to low Ohnesorge number (Oh) conditions is developed, which enables accurate prediction of the stretching-separation threshold. A non-monotonic, single-peak dependence of ligament volume and length on eccentricity is revealed, and a unified scaling relationship is established. Consequently, stable monodisperse satellite droplet trains are achieved with small diameters (～20 ± 2 μm), large spacing (～200 ± 5 μm), and high repetition rates (～18–43 kHz), satisfying the specifications for EUV droplet targets.