Differential absorption lidar combined with near-surface ozone monitoring were used to detect the vertical distribution of ozone in Tianjin from Jun. 23 to Sep. 28, 2018. The monitoring results indicated that the ozone concentration at 300 m above ground showed the same variation tendency as the monitoring values obtained near the ground. In the boundary layer of about 300 m to 1 000 m, the ozone concentration increased with height, but it then decreased at higher altitude. The maximum concentration occurred at approximately 1 000 m above ground. The times when the maximum and minimum concentrations occurred in the diurnal variation curve of ozone were delayed with increasing altitude. This phenomenon was influenced by the gradual transmission process of ozone precursors from the near-surface level to the upper air and the wastage of nitrogen oxide attributable to its oxidation reaction during the transmission process. Above 1 500 m, the diurnal variation curve of ozone showed a double-peak distribution. During the episodes of ozone pollution, the pollution zone with high ozone concentration could be detected frequently in the upper air. The ozone concentration at 1 000 m could reach about 570 μg/m3, and the thickness of the pollution zone could be greater than 1 km. The ozone at high altitude could last for days and sometimes did not dissipate completely at night. In this research, a mixing phenomenon of ozone pollution between high altitude and the near-surface level, which increased the degree of ozone contamination at the near-surface level, was identified 23 times during the ozone pollution days.