Abstract: Aircraft icing poses a significant threat to flight safety. To elucidate the meteorological conditions and cloud microphysical characteristics of aircraft icing and explore the relationship between icing and the thresholds of macro meteorological conditions, this study utilized aircraft observation data, along with radar and ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts, to analyze the weather conditions and cloud microphysical processes of a severe aircraft icing event in central and eastern Henan Province on December 10, 2018. The intensity of the icing event was also assessed. The event resulted from the combined effects of an upper-level trough, low-level shear, and surface cold high pressure. Warm, moist air at low levels flowing toward Henan ascended along the cold high pressure, forming an inversion layer with warm air above and cold air below, which promoted the accumulation of liquid water in the region. The icing area had a high liquid water content but a low ice water content. The liquid water content was significantly higher between altitudes of 550 to 750 hPa compared with other altitudes. The aircraft observation data was relatively consistent with the ERA5 reanalysis results. The severe icing area was located at an altitude of 3,630 m, with cloud temperatures between −8.2°C and −6.8°C, relative humidity ranging from 87% to 92%, an average cloud droplet concentration of 499.9 cm⁻³, and a maximum liquid water content of up to 0.87g m⁻³. In this area, large and small supercooled liquid droplets coexisted, with basically no ice crystal particles. Calculations indicated that the thresholds for light, moderate, and severe aircraft icing in areas rich in liquid water content were 0.05 g m⁻³, 0.20 g m⁻³, and 0.58 g m⁻³, respectively. Under an inversion layer strength of 1.93°C (100 hPa)⁻¹, vertical motion speed of −0.25 Pa s⁻¹–0.2 Pa s⁻¹, and horizontal convergence intensity of −3.73 kg m⁻² s⁻¹, the probability of the icing intensity reaching moderate or higher was 77%.