Abstract: The optical design of wide spectrum WFOV LLL collimating lens and the structure of lens set are introduced. The correction of the secondary spectrum of the WFOV LLL collimating lens are described emphatically. According to the primary aberration theory, the initial structure parameters of the system were solved. A design of a lens, whose operating wavelength is (0.486～0.863)μm, full field-of-view angle is and relative aperture is 1∶7.85, is presented on the basis of the theoretical calculation and the optimization of optical design software ZEMAX. The MTF of the lens, which is composed of five spherical lenses and one asphere lens, is better than 0.8 at the spatial frequency of 20lp/mm. The design makes the secondary spectrum of the lens to be at 0.01mm and other aberrations also met the requirement of the application.