Abstract: The prefabricated composite insulation facade panel with groove (abbreviated as composite panel) is a new type of non-load-bearing exterior sandwich wall panel. Its inner and outer leaves are autoclaved aerated concrete (abbreviated as AAC) panels, the sandwich layer adopts EPS insulation board, and the groove on the top can be used as cast-in-place concrete beam formwork. The flexural bearing capacity tests on 21 single-board panels and 42 composite panels are carried out, and studied are the effects of parameters such as AAC grade, AAC panel thickness, insulation panel thickness, shear-span ratio, strengthening measures, and loading cases on the failure modes and bearing capacity of the specimens. The test results show that when subjected to monotonic concentrated force loading, most of the single-board panels experience diagonal tension failure, while the composite panels experience either diagonal tension failure or punching failure. When subjected to a monotonic uniformly distributed load, all single-board panels experience flexural failure in the positive moment region. When the grade of AAC is increased from B05-A3.5 to B06-A5.0, the average cracking moment of single-board panels and the reinforced composite panels increase by 13.8% and 20.5%, respectively, while the ordinary composite panels show less significant variation in cracking moment. In the single-board specimen test, increasing the thickness of the aerated concrete board from 75 mm to 100 mm results in an average increase of 15.7% in the ultimate bearing capacity. For the ordinary composite panel, increasing the thickness of the inner flange from 75 mm to 100 mm results in an average increase of 68% in the cracking moment. The increase in insulation board thickness has no significant effect on the ultimate bearing capacity of the composite panels. By keeping the outer leaf of the composite panel at a thickness of 100 mm, when the inner leaf thickness is reduced to 75 mm, the ultimate bearing capacity under wind pressure loading condition is on average approximately 17.5% higher than that under wind suction loading condition. The reinforced composite panel has a smaller cracking load compared to the ordinary composite panel, but its ultimate bearing capacity is close to that of the ordinary composite panels that experienced diagonal tension failure, and greater than that of the ordinary notched plate specimens that experienced punching failure. The ultimate bearing capacity of ordinary composite panels with an inner leaf thickness of 75 mm is 104%-109.2% of the sum of the single inner and single outer leaf panels. The ultimate bearing capacity of ordinary composite panels with both inner and outer leaf thickness of 100 mm is 86.5%-120.2% of the sum of the ultimate bearing capacities of the inner and outer panels, which indicate that there is a certain combination effect between the inner and outer cladding panels and the intermediate insulation board of the composite panels. Under the concentrated force, with the decrease in shear span ratio, the cracking load and ultimate bearing capacity of the single-board panels both increase significantly. The ultimate bearing capacity of the single-board panels measured in the uniformly distributed load test falls between the concentrated force loaded specimens with shear-span ratios of 4.52 and 8.55.