Abstract: To investigate the diffusion capacity in the lower atmosphere during the high-temperature period in Henan Province and the impacts on ozone formation, surface meteorology data, reanalysis meteorological data and satellite data from 18 prefecture-level cities in Henan Province, as well as aerosol and ozone LIDAR detection data and radiosonde meteorological data from Zhengzhou observation station during June 2022 were used for analysis. The results showed that: (1)Under the persistent control of high pressure ridge, the highest surface temperatures nationwide occurred over Henan Province experienced in June 2022, with the extreme high exceeding 40 ℃. Coupled with intense ultraviolet radiation, it was in favorable conditions for ozone formation. (2) 4 regional ozone pollution cases occurred in June 2022, with approximately 66.7% cities exceeding the daily ozone standard. The maximum 8-hour average concentration of ozone on exceedance days ranged between 160 and 215 μg/m³, which were dominated by light pollution level. The highest it reached was 284 μg/m³, the severe pollution level. And, no city experienced the extreme severe level of ozone pollution. (3) Although controlled by the persistent of stable structure and high-temperature, the diffusion capacity in boundary layer were strong during ozone pollution days. The boundary layer height reached above 3 km. The surface wind speeds increased up to over 4 m/s in the afternoon. (4) With the strong diffusion capacity, pollutants spread over large space, where photochemistry occurred after the sufficient dilution. Thereby, no strong ozone formation occurred. The study showed that even in the extremely hot days with temperatures exceeding 40 ℃, as in June 16^th and 17^th 2022, the ozone pollution levels did not increase significantly as expected.