Magnetic frustrations can enhance quantum fluctuations in spin systems and lead to exotic topological insulating states.When coupled to mobile electrons,they may give rise to unusual non-Fermi liquid or metallic spin liquid states whose nature has not been well explored.Here,we propose a spin current Kondo mechanism underlying a series of non-Fermi liquid phases on the border of Kondo and magnetic phases in a frustrated three-impurity Kondo model.This mechanism is confirmed by renormal-ization group analysis and describes movable Kondo singlets called"holons"induced by an effective coupling between the spin current of conduction electrons and the vector chirality of localized spins.Similar mechanisms may widely exist in all frustrated Kondo systems and be detected through spin current noise measurements.