Abstract: We have obtained the laser plasma energy conversion eficiency for the low-Z and intermediate-Z element targets, driven by "Xingguang" high power laser at wavelength 1.06um and 0.53um. The results are compared with the previous results for the high-Z elements. The coefficiency of the energy absorption is also provided when the high power laser is line-focused on the thin film target. According to the diferent absorption coeficient between the thin film and thick target, we attempt to explain why the thin film target is more dificult to produce X-ray laser.