A Q-switched repetitive mini laser is developed by requirement of high beam-quality.The interrelations between the parameters of variable reflectivity mirror (VRM) and con-focal unstable resonator and their effects on laser intensity distributions are analyzed.A suit of resonator parameters is obtained to meet high beam-quality of outputting.In order to develop a mini adjust-free laser,a folded resonator is designed,where a cube corner prism is used as the folded mirror.Because linearly polarized light exists in the resonator,the laser can be run with an electro-optic Q-switch in a special polarization azimuth.Based on these theory analyses,an amount of experiments have been done.Using a xenon flash lamp with 32.4 J as the pump energy,single pulse laser output of high beam-quality and high dynamic to static ratio light spot is obtained,and its repetitive frequency is 1-10 Hz.When the laser works at the repetitive frequency of 3 Hz,an energy of 320.2 mJ,pulse width of 8.3 ns output beam is achieved,and its efficiency of the Q-switch is 95.5%,while the electro-optical efficiency is 0.99%.