The evolving pattern of ozone level in Hong Kong urban air has undergone various changes and corresponds to the regionalurban and economic development. We assess such changes by reviewing and analyzing the original ozone pollutant databasemonitored in central Hong Kong downtown area during the period of 1984–2002. Both fractal analysis and traditional statisticalmethods are adopted to estimate the ozone evolving characteristics during the studied period. It is found that the ozone evolvingpattern has strong self-similarity and the ozone pollution presents increasing trend in Hong Kong region in recent years basedon the analysis. The typical fractal dimensions for total time series are D=0.894 for available data set (N =5760) and D=0.859for complete data set with interpolation (N =6935), respectively. The fractal analysis can be used to assess the pollution trend inurban environment and may provide an alternative method for environmental study.