The purpose of this research is to simulate a Ti:sapphire cavity LASER by Kerr Lens Mode Locking (KLM). In oeder to do that, firstly we investigare all parts of a quasi-stable continuous To:sapphire cavity LASER. Then, regarding the nonlinear Kerr effect in the crystal, we determine the stability boundaries for the LASER in pulsed mode locking situation. Finally, a pair of prism system is designed to eleiminare the dispersion effects in system.