In order to improve the information transmission density and capacity of fiber Bragg grating sensing networks, a fiber Bragg grating multiplexing technology based on ultrasonic pulse excitation is proposed and experimental analysis is conducted. By introducing ultrasonic pulse excitation into a single grating and a grating string respectively, chirping occurs in the single grating and grating string. The experimental results indicate that in the single grating experiment, ultrasonic pulses reduce the relative reflectivity of the grating. In the grating string experiment, when the ultrasonic pulse causes the relative reflectance of one grating to decrease, the relative reflectance of the other gratings increases, which can effectively separate three gratings with similar spectra.