We present the moments formalism theory to study the deflection of the slow signal light in the cold atomic media, which is under the condition of the Gaussian control laser and electromagnetically induced transparency. Deflection, the interesting phenomenon on quantum coherence, is testified by analytic and numerical methods. Results show that, as the signal light propagating in the medium, there would be an observable deflection before the general diffraction. Influences of the coupling intensity on deflection phenomenon and the beam waist of the signal light in the medium are also investigated.
