Based upon the solutions of two-dimensional Laplance equations which may be solved with the conformal translation, we has deduced the lateral distribution of injection current in stripe geometry semiconductor lasers. We investigated the variations of lateral distribution of injection current density with different width of the central active regions and different electrode width in the case of low resistivity at resistance layer. If the central active region is thicker than electrode, the injection current density approximates constant in the central active region and quickly declines out the central active region.