The five mirror cavity of diode pumped Yb ∶YAG Kerr-lens mode-locked laser was analyzed theoretically in this paper. To get stable self-mode-locking in the experiment,the best parameters of the cavity had to be found. Compared the five mirror cavity with the four mirror cavity,it was found that the mode-locking was much more stable in the five mirror cavity. The reasonable explanation of five mirror cavity stable mode-locking was given in this paper by using stability region theory. And the Kerr-strength of the five-mirror cavity was calculated. It would provide a theoretical method for the modulation of the diode pumped kerr-lens mode-locked laser.