According to the basic principle of light-ray propagation, the collimating characteristic, the intensity distribution, the transfer efficiency of light energy and the transport coefficient for the laser diode ray in the fast axis direction passing through a cylindrical lens are analytically calculated and discussed. Based on analyzing a few of adjustable parameters, such as the radius of cylindrical lens, media index, media loss, lens location, and interface reflection, some conclusions are deduced that the location of cylindric lens directly influence the collimating effect of diode rays; lens radius, media index, and media loss not only influence spot size, intensity distribution, and energy transport, but also newly polarization distribution. That is to say, the cylindrical lens must be set out of focus slightly and the every parameter including the optical coating of transform system must be optimized. Above consequences are usefull to design a collimating system with micro-cylindrical lens that can considerably decrease the diverging angle of laser diode in fast axis and improve beam quality.