The invention discloses a wall-mounted type air conditioner indoor unit. The wall-mounted type air conditioner indoor unit comprises an indoor unit bottom plate (1) and a cross-flow fan blade (2) arranged on the indoor unit bottom plate (1). An air guide mechanism comprises a first air guide part (401) arranged on the indoor unit bottom plate (1) and a second air guide part (402) arranged outside the first air guide part (401). A passageway (7) for the cross-flow fan blade (2) to be taken out is arranged between the first air guide part (401) and a heat exchanger (5). The second air guide part (402) and a water collecting tray (3) are arranged in the passageway (7). The second air guide part (402) is connected to the water collecting tray (3). The water collecting tray (3) is detachably connected with the indoor unit bottom plate (1). The wall-mounted type air conditioner indoor unit has the beneficial effect of being convenient to detach.