With the development of radio-over-fiber (ROF), for getting 60 GHz millimeter wave signal, an improved solution based on secondary heterodyne method to produce eight times frequency millimeter wave is proposed. And a complete model for producing a millimeter wave system is presented. The feasibility of the system is analyzed theoretically and the influence of the laser line width and optical fiber dispersion on the system performances is analyzed. The system is simulated through OptiSystem software, the 60 GHz millimeter wave is demodulated which verifies the correctness of the scheme. The eye diagram of the system and the influence curve of the laser line width on the system bit error rate are obtained, which verifies that the narrow laser line width is helpful to reduce the system bit error rate.