Multi-phase injection-locked ring oscillators (MP-ILROs) are widely used for multi-phase clock generation, with their phase accuracy primarily determined by the inherent accuracy of the oscillator itself, due to the suppression of input signal errors. However, a quantitative analysis of the oscillator's sensitivity to input errors remains largely unexplored. This paper presents a phasor-based analysis of injection locking, revealing that the phase error sensitivity is influenced by factors such as injection strength and the free-running frequency of the oscillator. Simulation results align closely with theoretical calculations, validating the effectiveness of the proposed method.