Abstract：When discussing the correlation between precipitable water vapor (PWV) and fine particulate matter (PM2.5), traditional methods do not consider the impact of non-haze weather information contained in continuous data. So, this paper presents two data extraction standards: time standard and air quality index (AQI) level standard, which are used to obtain the corresponding PWV and PM2.5 sequence during haze. In order to solve the problem of discontinuity after data filtering, a non-parametric Spearman rank correlation coefficient（ρ） is introduced in this paper. By dealing with the discontinuous and non-equidistant PWV and PM2.5 sequence in different levels of the air quality during the haze-prone period in Beijing from 2014 to 2016, we learn that the average value after filtering of the first and fourth quarters in the three years is 0.661 3 and 0.628 0 respectively, and the overall average is 0.644 7, which indicates that the PWV and PM2.5 sequence have a monotonous and positive correlation under hazy weather. The correlation coefficients of both are small under the traditional analysis method (unfiltered), indicating that the analysis result is more specific and accurate after the data is selected.