The invention discloses a divided mining method for an inclined medium-thick ore body with an unstable false roof. The ore body is divided into panels along the strike, ore pillars of chambers are divided in the panels and a top pillar is reserved during stoping; an outside-vein slice drift, a layered linking roadway and a trackless stope preparation project of a chute mine are distributed on the upper panel of the ore body, and an upward air roadway is filled and is distributed at a position at the center of the ore pillars of the chambers and close to the lower panel; chambers are mined firstly and the ore pillars are mined secondly in the panels, and the chambers and the ore pillars are mined in an up-down layering manner; the stoping is performed from an ore removal crossdrift, the false roof and the ore body are mined in sequence, after ores are conveyed out by a carry-scraper, the false roof at the lower sub-layer is subjected to caving in advance by shallow holes, waste stones of the false roof are reserved in a stoping field, and the ore breaking compensation height is compensated in a layering filling manner, the stoping is performed on the lower sub-layer, and the laying caving is performed on the false roof after layering ore breaking and ore conveyed out, the operation is repeated for multiple times until the stoping field is stoped completely, and the bottom layer of the stoping field is filled to close to the back. By using the method, the operating safety, high mechanical degree, no removal of the waste stones of the false roof, low production cost, and low ore dilution loss can be realized.