Semiconductor materials such as Ge and InP etc, were investigated by the laser-induced chemical photolithography with argon ion laser. Two kinds of thresholds of light intensities were observrd respectively for the scanning photolithography on the surface and the rapid penetrated etching. The former has a lower threshold and the latter higher depending on the matting point. There exists a complicated relation between the etching rate and the light intensity. The etching rate decreased with the increase of the etching depth. Semiconductor species with higher dopant concentration were etched faster than those with lower dopant concentration.