The effect of the additive coloured noise on mode-competition of a two-mode laser is studied. By means of a linear stability analysis, considering τ as a small parameter, some conclusions have been obtained. In strong coupling, the effect of the additive colored noise on mode-competition is stronger than that of the additive white noise, and increases with the increasing of noise strength. In weak coupling, the effect of the additive colored noise on mode-competition is weaker than that of the additive white noise, and decreases with the increasing of coupling constants.