ArF excimer lasers characterized by short wavelength and high photon energy have important applications in the field of integrated circuit lithography, material processing, laser medicine, and so on. Structure of the compound cavity 193 nm ArF excimer laser is designed based on the linewidth narrowing techniques. Principles of the compound cavity laser are theoretically analyzed. Based on the characteristics of long cavity length in excimer laser system, the solutions for achieving effective mode-locking in compound cavity are proposed and experimentally verified. The laser output with nearly the same linewidth as the narrow-band cavity with dispersive elements and 4.02 times large energy is obtained. The laser efficiency and the energy stability are greatly improved as well.