The invention discloses a smoke exhaust efficiency evaluation method based on an orthogonality analysis method, and the method comprises the steps: (1) selecting smoke outlet set parameters which can influence tunnel smoke exhaust effect; (2) determining typical fire scenario of a tunnel; (3) selecting smoke exhaust efficiency and convection heat exhaust efficiency as examination indexes of smoke control effect; (4) adopting the orthogonality analysis method to design smoke outlet setting schemes; (5) calculating smoke exhaust and convection heat exhaust efficiency corresponding to the schemes; (6) selecting a factor level corresponding to a maximum value of the smoke exhaust and convection heat exhaust efficiency as an optimal value; (7) combining optimal values of factor levels to obtain an optimal setting scheme in first step; (8) adopting the smoke exhaust and convection heat exhaust efficiency and other conventional indexes to compare and analyze, and determining an optimal scheme. According to the invention, the method can comprehensively examine the influence from various parameters set in the smoke outlet to the smoke control effect, the smoke outlet setting mode can be optimized, and the smoke outlet setting optimal scheme can be provided.