The invention discloses a method for improving the consistency of the length of wind turbine blades with the same airfoil. The method comprises the steps that (1) fixed-point marks are made on the inner sides of formed dies of the wind turbine blades with the same airfoil, and the fixed-point marks are displayed on the surfaces of wind turbine blade precast products prepared by the formed dies andare close to the blade root parts; (2) the vertical distance D between the fixed-point marks and the end surfaces of the blade root parts of the wind turbine blades of actual requirement; and (3) primary flat cutting is conducted on the blade root rough end surface of each blade precast product produced by the corresponding formed die, the vertical distance F between the blade root end surfaces and the fixed-point marks after the primary cutting is measured, then F-D distance is used as secondary cutting cutter entering distance, and determination of the length of each wind turbine blade is completed. According to the method for improving the consistency of the length of the wind turbine blades with the same airfoil, the fixed point marks are arranged on the formed dies of the wind turbine blades, defects of error superposition when measuring the length of the blades are overcome, the operation steps are simplified, the production efficiency and the blade machining precision are improved, and the length uniformity of the wind turbine blades of the same airfoil are greatly improved.