Abstract: To meet the requirements of the adjustable delay of the pulse in the data synchronization processing of optical communication systems, a structural design scheme of adjusting the delay has been proposed. The light frequency shift characteristics of electro-optic intensity modulator (EOIM) have been analyzed, and based on the modulation of EOIM to the sideband and the light intensity, the delay adjusting could be achieved by regulating the pump light of the stimulated Brillouin scattering slow light. The mathematical model of the pulse delay has been established, and the modulation depth and the DC bias voltage varying with the pulse delay have been stimulated respectively at a fixed microwave frequency. From the experimental results, it is shown that the pulse delay gradually decreases with the increasing of modulation depth when the size of the DC bias voltage is half of the half-wave voltage, and the pulse delay gradually increases with the increasing of the DC bias voltage when the modulation depth is 1.39. The maximum delay can attain to 1.106 times the delay without modulation, which means adjustable delay is achieved effectively.