Abstract: GaN HEMT is used as the switch of the discharge circuit to achieve nanosecond pulse width. Due to the low total gate charge of GaN HMET, a GaN HEMT with small size is used to build the input stage of the driver circuit to respond to the control signal and control the discharge circuit switch. The circuit is built to drive the 860 nm laser and tested. The power supply voltage of the discharge circuit is 12 V, and the test results show that the maximum output pulse width of 8.8 ns corresponds to a peak power greater than 8 W, and the minimum output pulse width is 4 ns. Another circuit is designed and tested to achieve a larger pulse width adjustable range. The circuit realizes adjustable pulse width greater than 8.4 ns of output light. When the power supply voltage is 20 V and the pulse width of the input signal is 100 ns, the output optical peak power can reach 44 W. The area of the circuit is 10 mm×6 mm and 13 mm×11 mm. In order to realize further miniaturization of the drive circuit, a integration method is proposed for the two designed circuits. The proposed circuit is simple in structure, easy to realize integration and low in cost, which provides a new idea for the design of narrow pulse laser drive circuit.