The friction extrusion additive manufacturing (FEAM) process of 6061 aluminium alloy was successfully performed. The microstructure features, interface bonding mechanism and mechanical properties of single-pass one-layer, two-layer and nine-layer additive specimens were discussed in detail. It is found that under the process conditions of a spindle speed of 600 rpm and a moving speed of 300 mm/min, completely dense and defect-free 6061one-layer, two-layer and nine-layer additive specimens with layer thickness and width of 4 mm and 32 mm are obtained. The uniform microstructures of additive specimens are composed of fine and uniform equiaxed grains. The average grain size of one-layer and nine-layer additive specimens are 5.63±1.66 μm and 8.31±1.68 μm, which are significantly refined compared with the bar base metal (24.21±5.3 μm) . In the microstructures of single-pass one-layer additive specimen, the main strengthening phase b2 is almost completely dissolved and phase b′ is coarsed, so the average hardness is 64.7% of the bar base metal. The additive interface realizes metallurgical bonding and has the most significant degree of grain refinement. The hardness of interface reduce to 56.9% of the bar base metal because the strengthening phases b2 and b′ are almost completely dissolved. The average hardness of nine-layer specimen after multiple thermal cycles is 50.6% of the base metal. The nine-layer additive specimen exhibits excellent strength and toughness matching. The average tensile strength and elongation along the length direction of the additive specimen are 194 MPa and 34.6%, respectively, and the average tensile strength and elongation along the vertical direction of the additive specimen is 151.0 MPa and 10.4%, respectively.