Abstract: Based on the mining of a steeply inclined ore body by caving method to filling method，com‐ bined with the Platts theory method，material mechanics method，load transfer intersection line method and K.B.Rubeneit formula，the reasonable thickness of isolated pillars in the two areas is calculated. At the same time，the stability of isolated pillars in the process of multi-stage collaborative mining is analyzed by numer‐ ical simulation technology. The results show that based on the coupling analysis of various theoretical calcu‐ lation methods，the reasonable thickness of the isolated pillar of the steeply inclined ore body is determined to be 31 m，and the safety factor is 1.5. Under different mining schemes，the ground pressure activity does not change much，and the first mining of the first and third middle sections helps to reduce the ground pres‐ sure activity. The effective transfer stress of the filling body improves the stability of the mining process. The deep mining has little effect on the vertical displacement of the isolated pillar，and the pillar remains stable during the mining process. The plastic failure is mainly concentrated on the boundary of the filling stope. The first mining of the second and fourth middle sections can significantly reduce the plastic failure zone and improve the stability of the stope.

Key words: steeply inclined orebody, isolated pillar, theoretical calculation, numerical simulation, co‐ operative mining