The theories of atmospheric scintillation and its effects on laser engineering are combined and the dependence of loss factor on zenith distance are obtained. It has been proved that there exists a critical zenith below which the laser engineering can’t operate in accordance with the performance index predetermined without turbulence. From the model of the turbulent intensity distribution in Shanghai, we have calculated these characteristic quantities and got their values for two kinds of laser engineering. We investigated the scintillation characteristics of various wave shapes and their transformation, particularly the characteristics of laser beam wave and the problem of inclined path (for nonhomogeneous turbulence).