On the basis of experiments, a new conductive expression of photoconductive switch is proposed. According to this expression, the generation and sampling of high speed pulses, as well as the characteristics of photoelectron correlation measurement are analysed. The analysis agrees with experimental results and will be useful to the electronic measurement by photoelectron correlation method. A rather simple processing of devices is adopted. The rise time of photoconductive switch is 100 ps. It is sure that the rise time may obtain a ten-fold improvement only with ion-bombardment to the substrate.