The severe torrential rain attacked Henan province during July 17-22 in 2021 (abbreviation "21·7") whenever the process total rainfall amount reaches 1 122.6 mm and the hourly rain intensity at Zhengzhou national observation is up to 201.9 mm/h which broke through the meteorological record of hourly rain intensity extreme value in Chinese inland since 1951.The precipitation features and abnormality of atmospheric circulations and the environmental physical quantities were analyzed with the comparative analysis of physical quantities in the process of heavy rain over 50 mm in Zhengzhou and Hebi since 1981 based on the national and regional automatic meteorological observation data and the high resolution European central atmospheric reanalysis (ERA5).As shown by the results, the "21·7" severe rainfall process presents significant extremes in terms of cumulative precipitation, heavy rainfall coverage, daily rainfall, and hourly rainfall intensity.The eastern foot of Taihang Mountain and the windward slope of eastern Funiu Mountain are the only two locations with accumulated precipitation over 400 mm, which are closely related to topography.Anomalies in atmospheric circulation such as the enhancement and eastward extension of the South Asian high, the northward anomaly of the subtropical high, and the low-value system in low-latitude regions are responsible for the stable and lasting water vapor transport to Henan province.Water vapor convergence along Taihang and Funiu Mountain was below -10σ, showing significant extremes.Dynamic conditions are also apparent in the "21·7" process.With a deviation of 2σ-5σ from the historical climate, the divergence centers are located along the eastern foothills of Taihang Mountain and Funiu Mountain in 200 hPa.The deviation of 850 hPa vorticity from the climate state along Funiu Mountain is higher than that on the eastern foot of Taihang Mountain while the deviation of 700 hPa vertical velocity from the climate is more extreme on the eastern foot.For the same region since 1981, the standard deviation of 850 hPa vorticity and 700 hPa vertical velocity is the largest (least) or the secondary maximum (minimum) in the process of "21·7", which indicates the extreme rain.In the eastern foot of Taihang Mountain and Funiu Mountain, the deviations of 850 hPa convergence and 700 hPa vertical velocity are consistently greater than 3σ(-3σ) on average, positively correlated with daily rainfall.