Abstract: During the assembly of aircraft engine guide vanes, multiple blade selections and trial fittings are often necessary to meet the exhaust area’s technical specifications, which can negatively impact both assembly efficiency and the first-pass yield rate. To address the issue of suboptimal exhaust area assembly in turbine guide vanes, this paper investigates the measurement methods and principles of the exhaust area, establishes a mathematical model for measurement, and derives the key parameters and equations influencing the area. Numerical simulations are conducted to analyze these parameters, with the primary factors affecting the assembly area identified as blade profile thickness, blade flow channel length, and throat angle. Based on the simulation results, process adjustments were made to the blades, which were then validated, leading to improved assembly efficiency and an enhanced first-pass yield rate for the turbine guide vane.