A certain gently inclined multi-layer poor ore vein is located in the mining area, which simultaneously contains lead zinc, magnet, and sulfur copper minerals. Based on the characteristics of the ore body and its low grade, a pseudo inclined strip entry filling mining method is proposed for safer and more economical mining. FLAC3D software is used to simulate and analyze the roof displacement, pillar stress, and plastic zone distribution of different entry widths. Research shows that the pseudo inclined strip entry filling mining method can effectively reduce the loss and impoverishment of ore, greatly reduce mining and cutting engineering, increase the production capacity of the mining area, and achieve separate mining and transportation of different types of minerals. It can be flexibly applied to complex and variable gently inclined ore bodies. After numerical simulation analysis, the optimal entry width for this mine is 5 m-6 m.