The distribution of mechanical property in the weld zone of friction stir welded 7050 aluminum alloy joint along the plane perpendicular to the welding direction was experimentally investigated by the non-contact measurement method. The results show that the elastic modulus presents a W-shape distribution across the weld zone. The elastic modulus in the weld nugget zone is increased due to the grain refinement. In addition, the elastic modulus in the advancing side is slightly less than that in the retreating side possibly because of the relatively higher temperature in the advancing side during the welding process. The strength in the vicinity of weld center is decreased while the ductility is enhanced. The tensile strength and yield strength in the weld nugget zone and thermo-mechanically affected zone are significantly decreased while the elongation is increased due to the change of strengthening mechanism. In the heat affected zone the strength is decreased compared to the base material because the second phase grows up.