Abstract: Based on the photoconductive effect of the semiconductor,the photo-conductive switch has been developed.The photoconductive switch is biased at 4kV bias voltage,and can generate a electrical pulse in 50 ohm load with peak voltage～1.8kV,peak power～65kW and 16ns duration,when the switch is triggered by a laser pulse with 12 ns pulsewidth.In this paper,the keytechnologies of the photoconductive switch,such as dark resistance. carrier life、constant resistance etc,are described.