Based on the observational data of a self-developed fast-response air pressure sensor at the Atmospheric Boundary Layer and Atmospheric Environment Comprehensive Experimental Station in the Horqin area, Inner Mongolia in the summer of 2019, the characteristic parameters of the pressure fluctuations were calculated, and the spectral characteristics of the pressure fluctuations and the characteristics of the pressure standard deviation were studied. The results show that the self-developed fast-response air pressure sensor can reflect the rapid fluctuations of pressure, and the frequency response is close to 1 Hz. The variance spectra of the pressure fluctuations satisfy the n^-2 scaling law in the frequency range from 0.0006 to 0.5 Hz, and the peak frequency is lower than that of the wind speed and temperature. The normalized variance spectra of pressure fluctuations under different atmospheric stabilities merge into a single line in the high-frequency range and distribute around the stability parameter in the low-frequency range. The contribution of pressure fluctuations to turbulent energy is mainly at larger scales, while that of the wind speed and temperature is mainly at smaller scales. The standard deviation and fluctuation intensity of the pressure have obvious diurnal variation characteristics, which is strong during the daytime and weak during the nighttime.