Based on the proportion of construction land and the information entropy of land use, PM2.5 monitoring stations and air temperature monitoring stations in Xi"an were divided into urban, suburban and rural stations. Following this, the urban-rural distribution characteristics of PM2.5 and the correlation between urban (rural) PM2.5 concentration and urban heat island effect intensity (UHII) were discussed. Results showed that the urban-rural distribution characteristics of PM2.5 in Xi’an were different in different seasons. PM2.5 concentration difference between urban and rural areas (ΔPM2.5) was positive in spring, autumn and winter, and negative in summer. However, UHII was always positive and had a maximum value in winter and a minimum value in autumn. The correlation coefficient between urban PM2.5-UHII (RURBAN) was smaller than that of rural PM2.5-UHII (RRURAL), and both of the value were the largest in autumn and the smallest in summer. Furthermore, urban (rural) PM2.5-UHII showed a significant positive correlation in the morning and night time, and a negative correlation or irrelevance in the afternoon. Particularly, the period when the difference between RRURAL and RURBAN is large was consistent with the period when urban-rural ΔPM2.5 is negative. The lag time of urban PM2.5-UHII is later than that of rural PM2.5-UHII, and both of the correlation coefficients are the latest in summer and the earliest in winter.