We introduce a design method of the 1.57 μm eye-safe laser range-finder′s optical system. It utilizes the PW method according to the primary aberration theory of thin lens system to determine the initial structure of the range-finder′s optical system. A symmetric structure of range-finder′s optical system is designed by the Zemax software. After optimization, the symmetric optical system not only has the simple structure, convenient processing and assembly and low cost, but also satisfies the requirements of the performance of the range-finder′s emitting and receiving parts.