In high-speed machine device independent quantum key distribution (MDI-QKD) systems, high code rate is crucial to realize long-distance quantum communication. To achieve a higher code rate, each link of the system has more requirements on the light source. To meet the requirements, a pulse laser circuit for the high-speed MDI-QKD system is designed. According to the designed pulse laser circuit, by analog processing and driving the external or internal trigger signal, the pulse laser can be generated, and by using analog PID control and bidirectional TEC current control, the internel working temperature of the laser can be stabilized. The outgoing pulse laser can achieve an output with a repetition of up to 1.25 GHz, a full width at half maximum of 24.2 ps, an extinction ratio of 30 dB, a wavelength jitter of 0.95 pm and a wavelength tuning range of 2.014 nm, which is beneficial to the improvement of the code rate and meets the requirements of the high-speed MDI-QKD system.