When cross-correlation information of seismic ambient noise is used to study the seismic wave velocity changes in underground media before and after strong earthquakes,the characteristics of noise sources will affect the shape of cross-correlation function,which will affect the estimation of seismic velocity changes. Continuous waveform records from TQU station near the focal area of Lushan M_S7.0 earthquake between January 1 and December 31 of 2013 were used to calculate the power spectral density and probability density function to analyze the energy intensity characteristics of seismic ambient noise. The probability density functions of the degree of polarization and the polarization azimuth were calculated by frequency dependent polarization analysis to study the polarization characteristics of seismic ambient noise. The results indicate that there are many types of long-period seismic noise sources less than 0.05Hz in the study area,with high noise energy intensity and degree of polarization as well as obvious polarization azimuth. The single frequency microseisms(0.05～0.2Hz)has the polarization azimuth of 30° and 210°,and the noise energy is low. The polarization azimuth of double frequency microseisms(0.2～0.5Hz)ranges from 150° to 210°,and the noise energy is high,and its energy intensity has seasonal variation characteristics. The high-frequency noise greater than 1Hz mainly comes from human activities,and the noise energy level is significantly affected by the intensity of human activities. Therefore,even in continental regions far from the ocean,the influence of noise intensity and directional variation of noise sources should be noted when monitoring local seismic wave velocity changes using ambient noise.