Cupper vapor laser is a typical resonance－metastable transition laser. The laser－pulse is usually thought of occuring at the front edge of current pulse. Experiment shows that Ca;++ laser pulse is always at the front edge of current pulse under different condition. As for CuBr laser, the delay time of its laser pulse is related with the working temperature. Cupper atom is formed by means of the decomposition of CuBr into Cu;++, and then recombination of Cu;++. Consequently the recombination coefficient is bigger and the delay time of laser pulse gets longer when the working temperature is lower. And the recombination coefficient turns smaller and the laser pulse occurs ahead of time when the working temperature is higher.