Abstract: The irregular working surface with a knife handle shape has a complex and unique geomet⁃ ric form，which significantly increases the risk of impact and makes the evolution pattern difficult to pre⁃ dict. To study the impact risk and short-term dynamic evolution pattern of this type of working surface dur⁃ ing mining，by statistically analyzing the microseismic time series data of the irregular area of the working surface during mining，large energy events were selected as key nodes，and the impact risk distribution be⁃ fore the occurrence of the working surface was passively reconstructed using CT inversion. The inversion process divided the inversion intervals into 6 groups，and each group was further divided into 5 different depth layers for slicing. The height interval was set at -600 m to -580 m，with an interval of 5 m，so as to deeply analyze the distribution of impact risk in the coal seam and the roof and floor. The research results revealed the short-term evolution pattern of the impact risk during the mining of the irregular working sur⁃ face with a knife handle shape，provides a strong basis for the prediction and prevention of coal mine im⁃ pact-induced pressure disasters，effectively ensures the safety of coal mine production.

Key words: knifehandle shaped working face, passive CT inversion, impact risk, short-term evolu? tion rule, impact prediction