High brightness and high power light emitting diode (LED) based lamps have been identified as one of the solutions for energy saving light sources in illumination. Owing to its high energy efficiency, high color rendering and long life, LED lamps are promising. However, it is important to design a secondary optical lens for the LED lamps to obtain good output efficiency and a good light distribution pattern. In this paper, we proposed and developed a secondary optical lens design blueprint for LED stage lamps. A cone lens for stage lamps was designed and the desired illumination was achieved. The design procedure of the cone lens is presented. The simulation of the stage lamps is carried out in Tracepro 7.0. The results show that the cone lens can rearrange the luminous flux accurately and reasonably. A stage lamp with a uniform and circular luminous flux distribution is obtained.