Energy efficiency ratio is studied for long pulse laser where the pu lse width is millisecond order drilling.First of all,the different energy density long pulse laser dril ling depths are measured.In the experiment,the pulse width of laser is 1millisecond and then the energy efficie ncy ratio is obtained.The results show that the energy efficiency ratio of the laser drilling decreases as the laser energy density increases.Due to long-pulse laser power density is low and the shape of pulse is approximately rectangular,the one-dimensional steady-state heat conduction model is establi shed,and the relationship between drilling depth and the surface temperature is obtained.Then,the drilling depth i s measured in experiment as a boundary condition,and substituted into the above formula,and the surface temperature of the aluminum plate and gasification loss rate are calculated during the laser ir radiation.The results show that the higher the energy density of the laser,the higher the s urface temperature of the aluminum plate and the greater the gasification loss r ate.The obtained results are consistent with the reported ones in the literature .