The process and conditions of cesium atomic fountain were introduced with detailed discussion of the influence of the optical component on fountain optical system. An optical system for cesium fountain, used for co oling and launching atoms, was designed and set up. The parameters control such as intensity, detuning, light switch, beam quality meets to the demand of techno logy. The Cs magneto-optical trap for atomic fountain has been realized in this laser system. The work laid the groundwork for the realization of Cs atomic fountain.