Firing pulse is one of the key technologies of HVDC valves control as well as the research emphasis of domestic control and protection platform. This paper briefly introduces the generating principle of firing pulse used for valve control in HVDC transmission system, based on which the resolution about phase integrator and PLL tracking controller and their functions during the process of the firing pulse generation are analyzed. At last, the significance of equidistance pulses in 6 pulses system is analyzed, as well as how to minimize the equidistance error. This paper gives corresponding testing methods based on the design. Combining theory with practice, this paper describes the generation principle of firing pulse and the realization method, which provides a strong support for realizing home-made production for HVDC control and protection system.