Abstract: To meet the exhaust area requirements during the assembly of aero-engine guide vanes, multiple rounds of blade selection and trial assembly are often required, resulting in low assembly efficiency and a low first-pass yield rate. To address the issue of unsatisfactory exhaust area during the assembly of turbine guide vanes, this paper investigates the measurement method and principle of exhaust area, establishes a mathematical measurement model, derives the key parameters affecting the exhaust area along with the related equations, and conducts numerical simulations of these parameters. The results show that the main factors influencing the exhaust area during guide vane assembly include blade profile thickness, flow-path length, and throat angle. Based on the simulation results, the blade process parameters were adjusted and verified, which effectively improved the assembly efficiency and the first-pass qualification rate of turbine guide vanes.