We have analysed the results of the photorefractive two-wave mixing in LiNbO3∶Fe and LiNbO3∶Fe∶In controlled by an incoherent beam, and performed related experiments. Experimental results showed that the incoherent beam can effectively control the photorefractive two-wave coupling gain in a large range, suppress the fanning effect, increase the signal-to-noise ratio, and shorten the setup time of the two-wave mixing grating.