In order to satisfy the practical requirements that the view angle and the energy density distribution of the light beam should be adjustable in some specific lighting applications, an effective method to design LED illumination system with adjustable view angle is proposed. Considering the shortage of the traditional structure, a novel total internal reflection (TIR) lens is designed. The refractive surface is designed according to that the output light rays are parallel to the light axis. The TIR surface is designed according to that the total output light rays can realize the uniform illuminance on the remote target plane. A polycarb (PC) TIR lens with the view angle from 8° to 20° is designed as an example with this method. The simulation results show that, compared with the traditional structure, the average optical efficiency is increased by 13% and the average irradiance uniformity is increased by 17%. The volume of the novel TIR lens is decreased to about 1/5 of that of the traditional structure.