Time series analysis is one of the statistical method that examines relationship and time trend of different phenomenon. The analysis of air pollution in urban area can provide the possibility of prediction and planning for decreasing air pollution and its effects on people health. In this study, in order to examine air pollution changes in Isfahan and its correlation with climate parameters we used data of O 3 , NO, NO 2 , NO X , SO 2 and PM 10 and climate parameters such as maximum and minimum temperature, ratio humidity, wind direction and speed and rainfall were used during 1387 to 1388. Air pollution parameters changes were studied in different time bases including hourly, daily, monthly and seasonal. The results showed that concentration pattern of NO and CO was in harmony with traffic pattern and O 3 concentration increased with increasing of sun radiation. NO, NO 2 and CO had two peaks and O 3 had one peak during the day. There wasn’t any important hourly changes for SO 2 and PM 10 .The concentration of NO, SO 2 and PM 10 increased in cold seasons whereas O 3 concentration in warm seasons was more than cold seasons. There weren’t any important variation in during a week for all of the pollutants. Seasonal kendall test result showed that all of the pollutants except PM 10 had a significant (p 0.05) trend in Isfahan during two years. In most cases, the mean difference of pollutants concentrations between the stations were significant. Air pollution concentration had second and third grade regression relationship with time but third grade regression was true just for PM 10 and SO 2 in Ahmadabad station. PM 10 different average in Ahmadabad station and SO 2 different average in bakhtiardasht statio were significant with other stations. Spectoral density showed among all parameters there were seasonal and weekly variations. Correlation between air pollution and climate parameters was different for each pollutant and each year. The equations between them were multi variable. Wind direction and speed were important climate parameters in decreasing of pollutant especial for PM 10 and CO. There was a reversed relationship between ratio humidity and temperature for NO and SO 2 . SO 2 concentration showed low correlation with climate parameters. Most days of the year, the air quality index was unhealthy for sensitive people. PSI showed high correlation with wind direction and speed and mount of rainfall The number of the days above the standard level was high and in most case, PM 10 was the main pollutant in Isfahan. Key words : Time series, Air pollution, Trend, Climate parameters, Isfahan