A simple phased-array system with two anti-phase near infrared (NIR) light sources whose intensities are modulated sinusoidally at 200 MHz is established, and experiments for exploring the light distribution in homogeneous tissue phantom (0.25% intralipid) and the perturbations of intensity null and phase transition by absorbers are carried out. Results conform closely with the prediction by diffusion theory and the results of other groups［1,2］. Our measurements clearly demonstrate the distortion of the light distribution by the existence of absorbers and the effects on the perturbations caused by different sizes and locations of the objects. Particularly, we have studied the possibility of distinguishing between two absorbers and obtained initial results.