Abstract: This paper introduces the calculation methods and concepts related to the power spectral density and probability density function of seismic background noise. Taking actual data from the station as an example, a program algorithm for calculating the power spectral density and probability density function of noise using Matlab is provided. This method directly inputs text format data to calculate the probability density function of the power spectral density of background noise in a station. Taking the 24-hour continuous waveform record at Luoyang Seismic Station as an example, the entire process of implementing the removing instrument response, power spectral density calculation, octave calculation, and probability density function calculation of noise power spectral density from raw data is described in detail. This method is simple to program and suitable for evaluating the noise level of a single station. It has potential application value in the rapid selection of field stations.