Abstract: In this paper, the properties of laser propagation in media are have studied. Numerical solution shows that in media with quadratic or higher equivalent complex indexofrefraction n =n0+n2rm /rem , optical guiding will occure when laser propagates over. A certain distance. Whether considering saturation effect or not, we have got the similar results. Laser propagation parameters w, R-1 are dependent on n2 if we don’t consider saturation effect. Both the index of refraction and the gain make contributions to the emergence of optical guiding in media.